Material: Stainless steel 1.4305 (AISI 303), screw stainless steel A2-70.Features: does not damage the shaft, stronger clamping force than with set collars, even distribution of clamping forces, easy readjustment, precise bores in inch size. The threads of the metric screws DIN 912 are covered with a layer of polyamide. Tolerance b: +0.08 mm -0.25 mm. Temperature range: -40°C to +175°C.