diff --git a/HeatSink.scad b/HeatSink.scad
index 00839a2bac1c53e0b723d1a0c8314507e4868e10..4455b5c91a8c3325149a4bf1b6bfcbdfbed40324 100644
--- a/HeatSink.scad
+++ b/HeatSink.scad
@@ -159,19 +159,25 @@ module tri(w, h) {
 
 
 // length of the outlet
-x = 10;  // TODO: rename!!!!
-
-// difference between x and the split
-xx = 10;
+x = 5;  // TODO: rename!!!!
 
 // The profile of the funnel, ready for extrusion
 module funnel2D() {
   
   _y = hs_w/2 - fu_outlet_w;
-  translate([0, _y, 0]) square([x, fu_outlet_w]);
-  translate([0, -_y - fu_outlet_w, 0]) square([x, fu_outlet_w]);
-  
-  translate([0, 0, 0]) tri(xx, _y);
+
+  difference() {
+    union() {
+      translate([0, _y, 0]) square([x, fu_outlet_w]);
+      translate([0, -_y - fu_outlet_w, 0]) square([x, fu_outlet_w]);
+      
+      // air funnel split
+      translate([x, 0, 0]) tri(_y*4, hs_w);
+    }
+
+    // air funnel split
+    translate([x, 0, 0]) tri(x*2, _y*2);
+  }
 }