The left one is for return to cut and the right one is for the yield monitor. They have two different part numbers. The electrical parts are ALL identical. They are built so when you flip the housings over they will go on either side and seem to be identical. So what is the difference. Even on 2588's they list different part numbers for each side. THe reason I am asking is my yield monitor one shot craps and i have a new return to cut one on hand. Why can't I just flip it upside down and use it?