Central Pneumatic 5 Piece Pneumatic Tool Caps Helps to Prevent Normal Wear and Tear of Air Plugs When Banging Around on the Job Site or the Back of a Work Vehicle. Keep Dirt, Moisture and Other Foreign Contaminants From Entering the Tool Via the Air Inlet Valve One End Fits Over the 1/4" Air Tool Intake, the Opposite End Has a Ring for Attaching to the Tool to Prevent Loss