This is a replacement flexible rubber coupler with a drive pin mounted at the motor drive shaft/gear leg shaft junction on SE50 and SE60 thrusters.
If you have "sheared" your existing flexible coupler on your SE50 or SE60 thruster, this is the one to buy.
This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm.
www.P65Warnings.ca.gov