540 / 550 EP Motor Heatsink Navy Blue - Top
 
Will fit most 540 / 550 motors. Inner diameter is 35mm by 29mm wide.
 
The heatsink can have a fan mounted onto it. Drill holes have been tapered to fit the following fan measurements:
 
M3 3mm metric thread.
To fit a 24mm between centers fan (measured as if measuring one flat side of a square) 4 screw holes. 24mm apart (e.g. top right to top left fixing holes).