7-piece combination thread-cutting bit set from Wera in sturdy plastic box. 1/4" hexagon, fitting in holders according to DIN ISO 1173-D 6,3. With Rapidaptor quick-change function for mounting in the screwdriver or in the chuck of the electronically controlled drill. Very good power transmission via hexagonal shank. HSS = high-speed steel. Carefully tuned material elasticity ensures high tool life. Very good centring properties. Problem-free cutting. Perfect chip removal. Low risk of chipping. Precise return guidance.