Also known as Sems screws, these screws have a permanently attached but freely rotating tooth lock washer that bites into the mating surface for vibration resistance.

A freely rotating but permanently attached washer distributes pressure over a wider area than a flange, preventing damage to your material's surface.

Stainless steel screws have excellent corrosion resistance in most environments. They have a split lock washer to create tension and resist loosening from vibration.

A rubber O-ring under the head of these screws prevents leaks and seals out contaminants.