Pneumatic shaft-locking clamps are designed for quick change applications. They provide secure clamping of sliding shaft and spindle after position adjustment of parts and units in the machinery. Spring clamping occurs when air is removed, and unclamping when air is provided. Spring clamping and pneumatic unclamping mechanism prevents the decrease of clamping force by air leakage. The body is made from 5052A aluminum. The clamping shaft is made from 5052A anodized aluminum. The cover is made from 304 stainless steel.