diff --git a/Source/UI/UIChangeMaterialWnd.cpp b/Source/UI/UIChangeMaterialWnd.cpp
new file mode 100644
index 0000000..c45ce4b
--- /dev/null
+++ b/Source/UI/UIChangeMaterialWnd.cpp
@@ -0,0 +1,11 @@
+#include "UI/UIChangeMaterialWnd.h"
+
+// OFFSET: 0x005E1120
+
+// OFFSET: 0x005E1300
+// FUNCTION: fn_03874
+bool UIChangeMaterialWnd::Slot02() {
+  return true;
+}
+
+// OFFSET: 0x005E1310
diff --git a/Source/UI/UIChangeMaterialWnd.h b/Source/UI/UIChangeMaterialWnd.h
new file mode 100644
index 0000000..adbe3ee
--- /dev/null
+++ b/Source/UI/UIChangeMaterialWnd.h
@@ -0,0 +1,41 @@
+#ifndef RAGNAROK_SOURCE_UI_UICHANGEMATERIALWND_H
+#define RAGNAROK_SOURCE_UI_UICHANGEMATERIALWND_H
+
+#include "Contents/Items/ItemInfo.h"
+#include "UI/Window/UIFrameWnd.h"
+
+#include <cstdint>
+#include <vector>
+
+struct MaterialSlotPos {
+  /* 0000 */ int x;
+  /* 0004 */ int y;
+};
+
+class UIChangeMaterialWnd : public UIFrameWnd {
+public:
+  bool Slot02() override;
+  ItemInfo* GetItemAt(int x, int y);
+
+  /* 00BC */ std::uint32_t unknown_00BC;
+  /* 00C0 */ std::uint32_t unknown_00C0;
+  /* 00C4 */ int m_resultX;
+  /* 00C8 */ int m_resultY;
+  /* 00D0 */ ItemInfo m_resultItem;
+  /* 01C8 */ MaterialSlotPos m_materialPos[6];
+  /* 01F8 */ std::vector<ItemInfo> m_materials;
+};
+
+class UIChangeMaterialWnd_List : public UIFrameWnd {
+public:
+  void Move(int x, int y) override;
+};
+
+#if defined(_WIN32) && !defined(_WIN64)
+static_assert(offsetof(UIChangeMaterialWnd, m_resultX) == 0xC4);
+static_assert(offsetof(UIChangeMaterialWnd, m_resultItem) == 0xD0);
+static_assert(offsetof(UIChangeMaterialWnd, m_materialPos) == 0x1C8);
+static_assert(offsetof(UIChangeMaterialWnd, m_materials) == 0x1F8);
+#endif
+
+#endif
diff --git a/data/compile.json b/data/compile.json
index 3010ed3..bee3976 100644
--- a/data/compile.json
+++ b/data/compile.json
@@ -615,6 +615,7 @@
   "Source/UI/Text/UITextViewerLinks.cpp": 2,
   "Source/UI/Text/UITextViewerMessages.cpp": 2,
   "Source/UI/Text/UITransBalloonText.cpp": 2,
+  "Source/UI/UIChangeMaterialWnd.cpp": 2,
   "Source/UI/UILapineScrollBar.cpp": 2,
   "Source/UI/UILapineUpgradeBoxWnd.cpp": 2,
   "Source/UI/UIStaticBitmap.cpp": 2,