Like in chest, will certainly need an assistant to assist get exact measurements. Stand up straight, stretch, hold your one arm to your respective side and slightly bend it from knee. Start measuring the sleeve length from middle in the back of neck, go across shoulder, down for any arm, while following the bend of shoulder and elbow and end it at wrist bone. It is better to repeat process to get exact description. Add one inch as increment and consider measurement as your sleeve space.

The water heater will just be protected when the anode rod has enough metal hanging on out. The steel core wire keeps the sacrificial metal using a anode. Ensure inspect the anode for an exposed core wire every two years at the minimum.