diff --git a/eos/gamedata.py b/eos/gamedata.py
index 5ec2a1e14..c00c145a9 100644
--- a/eos/gamedata.py
+++ b/eos/gamedata.py
@@ -240,6 +240,7 @@ class Item(EqBase):
         self.__assistive = None
         self.__overrides = None
         self.__priceObj = None
+        self.__slot = None
 
     @property
     def attributes(self):
@@ -479,6 +480,21 @@ class Item(EqBase):
     def isCharge(self):
         return self.category.name == "Charge"
 
+    effectSlots = { 'loPower'  : 1,
+                    'medPower' : 2,
+                    'hiPower'  : 3,
+                    'rigSlot'  : 4,
+                    'subSystem': 5 }
+    @property
+    def slot(self):
+        if self.__slot is None:
+            self.__slot = 0
+            for effectName in self.effectSlots:
+                if effectName in self.effects:
+                    self.__slot = self.effectSlots[effectName]
+                    break
+        return self.__slot;
+
     def __repr__(self):
         return "Item(ID={}, name={}) at {}".format(
                 self.ID, self.name, hex(id(self))
diff --git a/gui/builtinMarketBrowser/itemView.py b/gui/builtinMarketBrowser/itemView.py
index 44e55f1a2..83be7e22f 100644
--- a/gui/builtinMarketBrowser/itemView.py
+++ b/gui/builtinMarketBrowser/itemView.py
@@ -268,13 +268,13 @@ class ItemView(Display):
             i += 1
         return revmap
 
-    slotColourMap = { 'loPower' : wx.Colour(250, 235, 204),
-                      'medPower': wx.Colour(188, 215, 241),
-                      'hiPower' : wx.Colour(235, 204, 209) }
+    slotColourMap = { 1: wx.Colour(250, 235, 204),
+                      2: wx.Colour(188, 215, 241),
+                      3: wx.Colour(235, 204, 209) }
 
     def columnBackground(self, colItem, item):
         if self.sFit.serviceFittingOptions["colorFitBySlot"]:
-            for effectName in self.slotColourMap:
-                if effectName in item.effects:
-                    return self.slotColourMap[effectName]
+            slot = item.slot;
+            if slot in self.slotColourMap:
+                return self.slotColourMap[slot]
         return wx.Colour(255, 255, 255)