Prusa i3 Sainsmart Y Endstop
Designed to maximise the space of the print plate, this Y end stop fits over the two 8mm threaded rods that hold the Y motor of a Prusa i3. There are checkouts and screw holes to suit a Sainsmart switch. The switch is activated when it hit the end of the carriage.
Hopefully this is useful to others building Prusa i3's.