The Dripless SI300 Contractor Grade Heavy Duty caulking gun has a steel revolving frame that fits 10 oz. cartridges and has a 14:1 thrust ratio for use with high viscosity materials such as silicone, latex, drywall, sub-floor adhesives, and polyurethanes. The gun has both drip and non-drip settings. On the non-drip setting, the rod retracts after each pull of the trigger, removing pressure from the tube to help prevent dripping. The hook on the back allows it to hang on a ladder, and a seal puncture tool and a spout cutter are built into the side of the gun for opening cartridges without a knife.Caulking guns, also called caulk or cartridge guns, dispense a controlled flow of products such as caulk, sealants, and adhesives from a tube or cartridge. A manual caulking gun consists of a frame which holds the tube, a trigger, and a rod which moves forward when the trigger is depressed, dispensing the product. Manual caulking guns have a thrust ratio; the higher the thrust ratio, the easier it is to dispense the caulk, sealant, or adhesive. Air-powered or pneumatic caulking guns also have a frame and a trigger, but are used with an air pressure regulator that pushes the product from the tube using air pressure instead of a rod.Dripless, Inc. manufactures caulking guns and caulking and painting accessories. The company, founded in 1992, is headquartered in Santa Rosa, CA.