diff --git a/src/GEMSpinner.cpp b/src/GEMSpinner.cpp
index d51bcc0..ca6eb3b 100644
--- a/src/GEMSpinner.cpp
+++ b/src/GEMSpinner.cpp
@@ -38,33 +38,37 @@
 #include "GEMSpinner.h"
 #include "constants.h"
 
-GEMSpinner::GEMSpinner(GEMSpinnerBoundariesByte boundaries_, bool loop_)
+GEMSpinner::GEMSpinner(GEMSpinnerBoundariesByte boundaries_, bool loop_, GEMSpinnerValueStringCallback valueStringCallback_)
   : _boundaries{ { .boundariesByte = { .step = boundaries_.step, .min = boundaries_.min < boundaries_.max ? boundaries_.min : boundaries_.max, .max = boundaries_.max > boundaries_.min ? boundaries_.max : boundaries_.min } } }
   , _type(GEM_VAL_BYTE)
   , _length(abs((boundaries_.max - boundaries_.min) / boundaries_.step) + 1)
   , _loop(loop_)
+  , _valueStringCallback(valueStringCallback_)
 { }
 
-GEMSpinner::GEMSpinner(GEMSpinnerBoundariesInt boundaries_, bool loop_)
+GEMSpinner::GEMSpinner(GEMSpinnerBoundariesInt boundaries_, bool loop_, GEMSpinnerValueStringCallback valueStringCallback_)
   : _boundaries{ { .boundariesInt = { .step = abs(boundaries_.step), .min = boundaries_.min < boundaries_.max ? boundaries_.min : boundaries_.max, .max = boundaries_.max > boundaries_.min ? boundaries_.max : boundaries_.min } } }
   , _type(GEM_VAL_INTEGER)
   , _length(abs((boundaries_.max - boundaries_.min) / boundaries_.step) + 1)
   , _loop(loop_)
+  , _valueStringCallback(valueStringCallback_)
 { }
 
 #ifdef GEM_SUPPORT_FLOAT_EDIT
-GEMSpinner::GEMSpinner(GEMSpinnerBoundariesFloat boundaries_, bool loop_)
+GEMSpinner::GEMSpinner(GEMSpinnerBoundariesFloat boundaries_, bool loop_, GEMSpinnerValueStringCallback valueStringCallback_)
   : _boundaries{ { .boundariesFloat = { .step = abs(boundaries_.step), .min = boundaries_.min < boundaries_.max ? boundaries_.min : boundaries_.max, .max = boundaries_.max > boundaries_.min ? boundaries_.max : boundaries_.min } } }
   , _type(GEM_VAL_FLOAT)
   , _length(abs((boundaries_.max - boundaries_.min) / boundaries_.step) + 1)
   , _loop(loop_)
+  , _valueStringCallback(valueStringCallback_)
 { }
 
-GEMSpinner::GEMSpinner(GEMSpinnerBoundariesDouble boundaries_, bool loop_)
+GEMSpinner::GEMSpinner(GEMSpinnerBoundariesDouble boundaries_, bool loop_, GEMSpinnerValueStringCallback valueStringCallback_)
   : _boundaries{ { .boundariesDouble = { .step = abs(boundaries_.step), .min = boundaries_.min < boundaries_.max ? boundaries_.min : boundaries_.max, .max = boundaries_.max > boundaries_.min ? boundaries_.max : boundaries_.min } } }
   , _type(GEM_VAL_DOUBLE)
   , _length(abs((boundaries_.max - boundaries_.min) / boundaries_.step) + 1)
   , _loop(loop_)
+  , _valueStringCallback(valueStringCallback_)
 { }
 #endif
 
@@ -196,3 +200,60 @@ void GEMSpinner::setValue(void* variable, int index, void* referenceVariable) {
     #endif
   }
 }
+
+
+byte GEMSpinner::produceStringForValue(char* stringBuffer, byte stringBufferLength, const GEMSpinnerValue& value, int valuePrecision) const
+{
+  if (_valueStringCallback != nullptr)
+  {
+    const char* const string = _valueStringCallback(value, _type, valuePrecision);
+    if (string != nullptr)
+    {
+      const size_t stringLength = MIN(strlen(string), (size_t)stringBufferLength - 1);
+      memcpy(stringBuffer, string, stringLength);
+      if (stringLength == stringBufferLength - 1)
+      {
+        stringBuffer[stringLength - 1] = '~'; // our "ellipsis"
+      }
+      stringBuffer[stringLength] = '\0';
+      return (byte)stringLength;
+    }
+  }
+
+  switch (_type)
+  {
+    case GEM_VAL_BYTE:
+      itoa(value.valByte, stringBuffer, 10);
+      break;
+    case GEM_VAL_INTEGER:
+      itoa(value.valInt, stringBuffer, 10);
+      break;
+    #ifdef GEM_SUPPORT_FLOAT_EDIT
+    case GEM_VAL_FLOAT:
+      dtostrf(value.valFloat, valuePrecision + 1, valuePrecision, stringBuffer);
+      break;
+    case GEM_VAL_DOUBLE:
+      dtostrf(value.valDouble, valuePrecision + 1, valuePrecision, stringBuffer);
+      break;
+    #endif
+    default:
+      *stringBuffer = '\0';
+      break;
+  }
+
+  return strlen(stringBuffer);
+}
+
+
+GEMSpinner& GEMSpinner::setValueStringCallback(GEMSpinnerValueStringCallback callback)
+{
+  _valueStringCallback = callback;
+  return *this;
+}
+
+
+GEMSpinner& GEMSpinner::removeValueStringCallback()
+{
+  _valueStringCallback = nullptr;
+  return *this;
+}
diff --git a/src/GEMSpinner.h b/src/GEMSpinner.h
index c3bb44a..b13b822 100644
--- a/src/GEMSpinner.h
+++ b/src/GEMSpinner.h
@@ -94,6 +94,8 @@ struct GEMSpinnerValue {
   };
 };
 
+typedef const char* const (*GEMSpinnerValueStringCallback)(GEMSpinnerValue /* value */, byte /* value type */, int /* value precision */);
+
 // Declaration of GEMSpinner class
 class GEMSpinner {
   friend class GEM;
@@ -105,21 +107,25 @@ class GEMSpinner {
       @param 'loop_' (optional) - whether iteration over options should be looped
       values GEM_LOOP (alias for true)
     */
-    GEMSpinner(GEMSpinnerBoundariesByte boundaries_, bool loop_ = false);
-    GEMSpinner(GEMSpinnerBoundariesInt boundaries_, bool loop_ = false);
+    GEMSpinner(GEMSpinnerBoundariesByte boundaries_, bool loop_ = false, GEMSpinnerValueStringCallback valueStringCallback_ = nullptr);
+    GEMSpinner(GEMSpinnerBoundariesInt boundaries_, bool loop_ = false, GEMSpinnerValueStringCallback valueStringCallback_ = nullptr);
     #ifdef GEM_SUPPORT_FLOAT_EDIT
-    GEMSpinner(GEMSpinnerBoundariesFloat boundaries_, bool loop_ = false);
-    GEMSpinner(GEMSpinnerBoundariesDouble boundaries_, bool loop_ = false);
+    GEMSpinner(GEMSpinnerBoundariesFloat boundaries_, bool loop_ = false, GEMSpinnerValueStringCallback valueStringCallback_ = nullptr);
+    GEMSpinner(GEMSpinnerBoundariesDouble boundaries_, bool loop_ = false, GEMSpinnerValueStringCallback valueStringCallback_ = nullptr);
     #endif
     GEMSpinner& setLoop(bool mode = true);  // Explicitly set or unset loop mode
     bool getLoop();                         // Get current value of loop mode
     GEM_VIRTUAL GEMSpinnerValue getOptionNameByIndex(void* variable, int index);  // Get option by its index
+    GEM_VIRTUAL byte produceStringForValue(char* stringBuffer, byte stringBufferLength, const GEMSpinnerValue& value, int valuePrecision) const;
+    GEM_VIRTUAL GEMSpinner& setValueStringCallback(GEMSpinnerValueStringCallback callback);
+    GEM_VIRTUAL GEMSpinner& removeValueStringCallback();
   protected:
     GEMSpinnerBoundaries _boundaries;
     byte _type;
     int _length;
     bool _loop = false;
     byte getType();
+    GEMSpinnerValueStringCallback _valueStringCallback;
     int getLength();
     GEM_VIRTUAL int getSelectedOptionNum(void* variable);
     GEM_VIRTUAL void setValue(void* variable, int index, void* referenceVariable = nullptr);  // Assign value of the selected option to supplied variable, optionally setting reference variable for counting options
diff --git a/src/GEM_adafruit_gfx.cpp b/src/GEM_adafruit_gfx.cpp
index 8ec89fd..51eed9d 100644
--- a/src/GEM_adafruit_gfx.cpp
+++ b/src/GEM_adafruit_gfx.cpp
@@ -425,22 +425,8 @@ void GEM_adafruit_gfx::printMenuItem(GEMItem* menuItemTmp, byte yText, byte yDra
           case GEM_VAL_SPINNER:
             {
               GEMSpinner* spinner = menuItemTmp->spinner;
-              switch (spinner->getType()) {
-                case GEM_VAL_BYTE:
-                  itoa(*(byte*)menuItemTmp->linkedVariable, valueStringTmp, 10);
-                  break;
-                case GEM_VAL_INTEGER:
-                  itoa(*(int*)menuItemTmp->linkedVariable, valueStringTmp, 10);
-                  break;
-                #ifdef GEM_SUPPORT_FLOAT_EDIT
-                case GEM_VAL_FLOAT:
-                  dtostrf(*(float*)menuItemTmp->linkedVariable, menuItemTmp->precision + 1, menuItemTmp->precision, valueStringTmp);
-                  break;
-                case GEM_VAL_DOUBLE:
-                  dtostrf(*(double*)menuItemTmp->linkedVariable, menuItemTmp->precision + 1, menuItemTmp->precision, valueStringTmp);
-                  break;
-                #endif
-              }
+              GEMSpinnerValue valueTmp = spinner->getOptionNameByIndex(menuItemTmp->linkedVariable, _valueSelectNum);
+              spinner->produceStringForValue(valueStringTmp, sizeof(valueStringTmp), valueTmp, menuItemTmp->precision);
               printMenuItemValue(valueStringTmp, -1 * calculateSpriteOverlap(GEM_ICON_SPINNER_ARROWS));
               drawSprite(_agfx.width() - getSprite(GEM_ICON_SPINNER_ARROWS)->width - 1 * _spriteSize, yDraw, GEM_ICON_SPINNER_ARROWS, color, menuItemTmp);
             }
diff --git a/src/GEM_u8g2.cpp b/src/GEM_u8g2.cpp
index 31459fa..6b8a7b5 100644
--- a/src/GEM_u8g2.cpp
+++ b/src/GEM_u8g2.cpp
@@ -496,42 +496,12 @@ void GEM_u8g2::printMenuItems() {
                 GEMSpinner* spinner = menuItemTmp->spinner;
                 if (_editValueMode && menuItemTmp == _menuPageCurrent->getCurrentMenuItem()) {
                   GEMSpinnerValue valueTmp = spinner->getOptionNameByIndex(menuItemTmp->linkedVariable, _valueSelectNum);
-                  switch (spinner->getType()) {
-                    case GEM_VAL_BYTE:
-                      itoa(valueTmp.valByte, valueStringTmp, 10);
-                      break;
-                    case GEM_VAL_INTEGER:
-                      itoa(valueTmp.valInt, valueStringTmp, 10);
-                      break;
-                    #ifdef GEM_SUPPORT_FLOAT_EDIT
-                    case GEM_VAL_FLOAT:
-                      dtostrf(valueTmp.valFloat, menuItemTmp->precision + 1, menuItemTmp->precision, valueStringTmp);
-                      break;
-                    case GEM_VAL_DOUBLE:
-                      dtostrf(valueTmp.valDouble, menuItemTmp->precision + 1, menuItemTmp->precision, valueStringTmp);
-                      break;
-                    #endif
-                  }
+                  spinner->produceStringForValue(valueStringTmp, sizeof(valueStringTmp), valueTmp, menuItemTmp->precision);
                   printMenuItemValue(valueStringTmp, -1 * calculateSpriteOverlap(GEM_ICON_SPINNER_ARROWS));
                   drawSprite(_u8g2.getDisplayWidth() - getSprite(GEM_ICON_SPINNER_ARROWS)->width - 1, yDraw, GEM_ICON_SPINNER_ARROWS, menuItemTmp);
                   drawEditValueCursor();
                 } else {
-                  switch (spinner->getType()) {
-                    case GEM_VAL_BYTE:
-                      itoa(*(byte*)menuItemTmp->linkedVariable, valueStringTmp, 10);
-                      break;
-                    case GEM_VAL_INTEGER:
-                      itoa(*(int*)menuItemTmp->linkedVariable, valueStringTmp, 10);
-                      break;
-                    #ifdef GEM_SUPPORT_FLOAT_EDIT
-                    case GEM_VAL_FLOAT:
-                      dtostrf(*(float*)menuItemTmp->linkedVariable, menuItemTmp->precision + 1, menuItemTmp->precision, valueStringTmp);
-                      break;
-                    case GEM_VAL_DOUBLE:
-                      dtostrf(*(double*)menuItemTmp->linkedVariable, menuItemTmp->precision + 1, menuItemTmp->precision, valueStringTmp);
-                      break;
-                    #endif
-                  }
+                  spinner->produceStringForValue(valueStringTmp, sizeof(valueStringTmp), *static_cast<const GEMSpinnerValue*>(menuItemTmp->linkedVariable), menuItemTmp->precision);
                   printMenuItemValue(valueStringTmp, -1 * calculateSpriteOverlap(GEM_ICON_SPINNER_ARROWS));
                   drawSprite(_u8g2.getDisplayWidth() - getSprite(GEM_ICON_SPINNER_ARROWS)->width - 1, yDraw, GEM_ICON_SPINNER_ARROWS, menuItemTmp);
                 }