Seastar - Rear Mount Helm - 1.7 Cubic Inch - HH52613 Efficient, safe and reliable. Easy to install. Feature helm rotor supported by 3 roller bearings, ball bearing piston race, simplified integrated metal construction, field replaceable shaft seal, 1/4'' NPT port threads, internal pressure relief valve, front of dash fill, lock valve for positive rudder lock, patented bleed tubes and internal air pocket to eliminate oil expansion overflow. Compact and stylish. Fits 3'' dash hole for round look with retro fit of 4-1/2'' dash hole for standard Seastar square look. Type-SeaStar 1.7, Mount-Rear