Made of fibreglass reinforced nylon, the Holdfast Vacuum Chuck Head features a machined aluminium threaded collar for strength. Closed-cell foam o-rings guarantee a positive seal to hold the work firmly while providing a small amount of give that prevents the work from coming loose in the event of a minor tool catch. Vacuum chuck heads are versatile and seal flat, concave, and convex surfaces. Double O-ring seals provide the optimal vacuum seal. Available in standard spindle threads 1", 1.25", and 33mm.