This is a set of 5 (Five) Haltec H-5265 standard bore lock on air chucks. These are specially designed air chucks that lock onto the cap threads of a Standard Bore valve stem when the sliding sleeve is pushed to the forward position. The chuck releases when the sleeve is pulled back. These air chucks connect with a 1/4″” NPT thread size. Haltec is a leading manufacturer of inflation systems and maintains its leadership position as a major manufacturer of specialized tire valve systems.