These 1/2" Power-Seal® Worm Gear Clamps are made of high quality stainless steel. The interlocking "square knot" design will not pull apart. This design enables higher sealing pressure even at lower applied torque ranges, such as installing with a screwdriver. Power-Seal Clamps are general purpose and suited for heater and coolant hoses, as well as air intake & bilge pump lines in corrosive and non-corrosive environments. They are available in a variety of stainless steel grades and finishes with 5/16 slotted hex head screw.