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.