diff --git a/package.json b/package.json
index 281ac75..8551adc 100644
--- a/package.json
+++ b/package.json
@@ -25,11 +25,14 @@
     "watchapp": {
       "watchface": true
     },
-    "messageKeys": [
-      "BACKGROUND_COLOR",
-      "DIGIT_COLOR",
-      "FRAME_COLOR"
-    ],
+    "messageKeys": {
+      "BACKGROUND_COLOR": 10000,
+      "DIGIT_COLOR": 10001,
+      "FRAME_COLOR": 10002,
+      "TIME_FORMAT_OVERRIDE": 10010,
+      "12H_START": 10011,
+      "24H_START": 10012
+    },
     "capabilities": [ "configurable" ],
     "resources": {
       "media": [
diff --git a/src/c/main.cpp b/src/c/main.cpp
index 2ae0a86..89e8045 100644
--- a/src/c/main.cpp
+++ b/src/c/main.cpp
@@ -39,19 +39,18 @@ protected:
     TickTimerStart(HOUR_UNIT);
     TickTimerStart(USE_SECONDS_INSTEAD_OF_MINUTES ? SECOND_UNIT : MINUTE_UNIT);
     UpdateTime(false);
+    ApplySettings();
   }
 
   void UpdateTime(bool animate=true) {
     DateTime dateTime = DateTime::Now();
-    int hour = dateTime.GetHour();
+    int hour = settings::FormatHour(dateTime.GetHour());
     int minute = USE_SECONDS_INSTEAD_OF_MINUTES ? dateTime.GetSecond() : dateTime.GetMinute();
-    bool is_24h = clock_is_24h_style();
-    if (!is_24h) hour %= 12;
 
-    digitLayers[0].SetDigitCount(is_24h ? 3 : 2);
-    digitLayers[1].SetDigitCount(is_24h ? 24 : 12);
-    digitLayers[2].SetDigitCount(6);
-    digitLayers[3].SetDigitCount(10);
+    // digitLayers[0].SetDigitCount(is_24h ? 3 : 2);
+    // digitLayers[1].SetDigitCount(is_24h ? 24 : 12);
+    // digitLayers[2].SetDigitCount(6);
+    // digitLayers[3].SetDigitCount(10);
     this->digitLayers[0].RotateTo(hour / 10, animate);
     this->digitLayers[1].RotateTo(hour, animate);
     this->digitLayers[2].RotateTo(minute / 10, animate);
@@ -61,33 +60,33 @@ protected:
   void OnTick(tm &tick_time, TimeUnits units_changed) {
     UpdateTime(true);
   }
-};
-
-namespace {
+  
+public:
   void ApplySettings() {
-    Pebble::Window window = window_stack_get_top_window();
-    window.SetBackgroundColor(settings::GetBackgroundColor());
-    window.MarkDirty();
+    this->SetBackgroundColor(settings::GetBackgroundColor());
+    this->UpdateTime(true);
 
     bitmaps::SetDigitColor(settings::GetDigitColor());
     bitmaps::SetFrameColor(settings::GetFrameColor());
   }
+};
 
-  void HandleMsg(DictionaryIterator *iter, void *context) {
+namespace {
+  void HandleMsg(DictionaryIterator* iter, void* context) {
     settings::HandleMsg(iter);
-    ApplySettings();
+    static_cast<MainWindow*>(context)->ApplySettings();
   }
 }
 
 MAIN {
   bitmaps::Init();
   settings::Load();
-  app_message_register_inbox_received(HandleMsg);
-  app_message_open(64, 64); // inbox, outbox
-
   MainWindow window;
   window.StackPush(true);
-  ApplySettings();
+
+  app_message_set_context(&window);
+  app_message_register_inbox_received(HandleMsg);
+  app_message_open(64, 64); // inbox, outbox
 
   app_event_loop();
 
diff --git a/src/c/settings.cpp b/src/c/settings.cpp
index 1bccebb..86a1217 100644
--- a/src/c/settings.cpp
+++ b/src/c/settings.cpp
@@ -1,3 +1,4 @@
+#include <@rebble/sdk-c-utils/macros.h>
 #include "settings.hpp"
 
 // Built-in GColorFromRGBA doesn't seem to work in C++11 :(
@@ -16,28 +17,49 @@ namespace settings {
     GColor backgroundColor = GColorWhite;
     GColor digitColor = GColorBlack;
     GColor frameColor = GColorBlack;
+    int time_format_override = 0;
+    int time_12h_start = 1;
+    int time_24h_start = 0;
   }
 
   void Save() {
     persist_write_data(MESSAGE_KEY_BACKGROUND_COLOR, &backgroundColor, sizeof(GColor));
     persist_write_data(MESSAGE_KEY_DIGIT_COLOR, &digitColor, sizeof(GColor));
     persist_write_data(MESSAGE_KEY_FRAME_COLOR, &frameColor, sizeof(GColor));
+    persist_write_data(MESSAGE_KEY_TIME_FORMAT_OVERRIDE, &time_format_override, sizeof(int));
+    persist_write_data(MESSAGE_KEY_12H_START, &time_12h_start, sizeof(int));
+    persist_write_data(MESSAGE_KEY_24H_START, &time_24h_start, sizeof(int));
   }
 
   void Load() {
     persist_read_data(MESSAGE_KEY_BACKGROUND_COLOR, &backgroundColor, sizeof(GColor));
     persist_read_data(MESSAGE_KEY_DIGIT_COLOR, &digitColor, sizeof(GColor));
     persist_read_data(MESSAGE_KEY_FRAME_COLOR, &frameColor, sizeof(GColor));
+    persist_read_data(MESSAGE_KEY_TIME_FORMAT_OVERRIDE, &time_format_override, sizeof(int));
+    persist_read_data(MESSAGE_KEY_12H_START, &time_12h_start, sizeof(int));
+    persist_read_data(MESSAGE_KEY_24H_START, &time_24h_start, sizeof(int));
   }
 
-  void HandleMsg(DictionaryIterator *iter) {
+  void HandleMsg(DictionaryIterator* iter) {
     if (auto tuple = dict_find(iter, MESSAGE_KEY_BACKGROUND_COLOR)) backgroundColor = GColorFromHEX(tuple->value->int32);
     if (auto tuple = dict_find(iter, MESSAGE_KEY_DIGIT_COLOR)) digitColor = GColorFromHEX(tuple->value->int32);
     if (auto tuple = dict_find(iter, MESSAGE_KEY_FRAME_COLOR)) frameColor = GColorFromHEX(tuple->value->int32);
+    if (auto tuple = dict_find(iter, MESSAGE_KEY_TIME_FORMAT_OVERRIDE)) time_format_override = tuple->value->int8;
+    if (auto tuple = dict_find(iter, MESSAGE_KEY_12H_START)) time_12h_start = tuple->value->int8;
+    if (auto tuple = dict_find(iter, MESSAGE_KEY_24H_START)) time_24h_start = tuple->value->int8;
     Save();
   }
 
   GColor GetBackgroundColor() {return backgroundColor;}
   GColor GetDigitColor() {return digitColor;}
   GColor GetFrameColor() {return frameColor;}
+
+  int FormatHour(int hour) {
+    const bool is_24h = time_format_override ? time_format_override == 24 : clock_is_24h_style();
+    if (is_24h) {
+      return (hour + 24 - time_24h_start) % 24 + time_24h_start;
+    } else {
+      return (hour + 12 - time_12h_start) % 12 + time_12h_start;
+    }
+  }
 }
\ No newline at end of file
diff --git a/src/c/settings.hpp b/src/c/settings.hpp
index 3b62e9c..541388f 100644
--- a/src/c/settings.hpp
+++ b/src/c/settings.hpp
@@ -5,8 +5,9 @@
 namespace settings {
   void Save();
   void Load();
-  void HandleMsg(DictionaryIterator *iter);
+  void HandleMsg(DictionaryIterator* iter);
   GColor GetBackgroundColor();
   GColor GetDigitColor();
   GColor GetFrameColor();
+  int FormatHour(int hours);
 }
diff --git a/src/pkjs/config.js b/src/pkjs/config.js
index 0a5a879..d0e590c 100644
--- a/src/pkjs/config.js
+++ b/src/pkjs/config.js
@@ -29,6 +29,42 @@ module.exports = [
       },
     ]
   },
+  { 
+    type: "section", 
+    items: [ 
+      {
+        type: "heading", 
+        defaultValue: "Time Format",
+      },
+      {
+        label: "Time Format",
+        messageKey: "TIME_FORMAT_OVERRIDE",
+        type: "select",
+        options: [
+          {label: "Use system", value: 0},
+          {label: "12 hour", value: 12},
+          {label: "24 hour", value: 24},
+        ],
+        defaultValue: 0,
+      },
+      {
+        label: "12h Range",
+        description: "Most people want '1:00 to 12:59'. Some countries use '0:00 to 11:59' instead.",
+        messageKey: "12H_START",
+        type: "select",
+        options: Array.from({length: 12}, (_, i) => ({value: i, label: `${i}:00 to ${i + 11}:59`})),
+        defaultValue: 1,
+      },
+      {
+        label: "24h Range",
+        description: "Most people want '0:00 to 23:59'.",
+        messageKey: "24H_START",
+        type: "select",
+        options: Array.from({length: 24}, (_, i) => ({value: i, label: `${i}:00 to ${i + 23}:59`})),
+        defaultValue: 0,
+      },
+    ]
+  },
   {
     type: "submit",
     defaultValue: "Save Settings",
diff --git a/src/pkjs/index.js b/src/pkjs/index.js
index 9a8e20b..fbdbe47 100644
--- a/src/pkjs/index.js
+++ b/src/pkjs/index.js
@@ -1,3 +1,48 @@
 var Clay = require('pebble-clay');
 var clayConfig = require('./config');
-var clay = new Clay(clayConfig);
\ No newline at end of file
+var clay = new Clay(clayConfig);
+
+
+// Patch `select` to return integers instead of strings
+
+function disable() {
+  if (this.$manipulatorTarget.get('disabled')) { return this; }
+  this.$element.set('+disabled');
+  this.$manipulatorTarget.set('disabled', true);
+  return this.trigger('disabled');
+}
+
+function enable() {
+  if (!this.$manipulatorTarget.get('disabled')) { return this; }
+  this.$element.set('-disabled');
+  this.$manipulatorTarget.set('disabled', false);
+  return this.trigger('enabled');
+}
+
+function hide() {
+  if (this.$element[0].classList.contains('hide')) { return this; }
+  this.$element.set('+hide');
+  return this.trigger('hide');
+}
+
+function show() {
+  if (!this.$element[0].classList.contains('hide')) { return this; }
+  this.$element.set('-hide');
+  return this.trigger('show');
+}
+
+clay.components.select.manipulator = {
+  get: function() {
+    return parseInt(this.$manipulatorTarget.get('value'));
+  },
+  set: function(value) {
+    if (this.get() === value) { return this; }
+    this.$manipulatorTarget.set('value', value);
+    return this.trigger('change');
+  },
+  disable: disable,
+  enable: enable,
+  hide: hide,
+  show: show
+};
+  
\ No newline at end of file