This 1 1/16" six point socket style prop wrench is made of high tensile strength, indestructible nylon. It is totally resistant to fuel, sun, salt water, and other chemicals. The Prop Master is less expensive than metal wrenches which rattle and can cause damage to your boat. However, it has plenty of brawn to get the job done. The Prop Master will tighten all 1 1/16" propeller nuts without slipping or stripping. (OMC - over 40 HP, Mercury - over 50 HP) High visibility color makes it easy to locate in dark boat compartments. The Prop Master also has a 9/16" garboard drain plug socket on the reverse side. Will not corrode in the salt water environment.