Quality shaft anodes meet stringent Mil-Spec standards for protection against galvanic corrosion.Sea Shield streamlined collar anodes are pressure die cast and conform to the highest Mil-Spec standards. Offered here in zinc material for use in saltwater. They install with just 2 deep-slotted stainless steel machine screws which provide maximum torque, and are extremely durable. Offered in a range of diameters to accommodate shafts from 3/4"ID up to 4"ID. For stainless steel or bronze shafts.Key FeaturesZinc material for saltwaterPressure die castMeet highest Mil-Spec standardsDeep slotted stainless steel screws allow for maximum torqueFor stainless steel or bronze shaftsEasy size verification inside and outsideInnovative O-rings keep screws from falling out Type Shaft Size Length Outside Dim Weight Box Qty SL-0750 3/4" 1-3/4" 1-7/8" 0.650 50 SL-0875 7/8" 1-7/8" 1-7/8" 0.825 50 SL-1000 1" 2" 2-1/4" 1.000 50 SL-1125 1-1/8" 2" 2-1/4" 0.975 50 SL-1250 1-1/4" 2" 2-3/8" 0.980 50 SL-1375 1-3/8" 2-1/2" 2-5/8"