Dear Mr. Pushit,
Many thanks for your message.
Please, find our explanations as follows:
WR 31
Standard straightening roll for the given wire size range acc. to the attached specification sheet WR.PDF, max. wire speed approx. 20 m/s. The consists of an inner ring, the balls in two rows and the outer ring (extended thickness for carrying the groove).
WR 31 RK PETP
Customized straightening roll, consisting of a bearing and a PET plastic sleeve for straightening soft wires, e. g. Aluminum, Copper etc.
WR 31 HL
Standard replacement straightening roll for carrying high loads according our specification sheet HL.PDF. HL 31 G including screw bolt and HL 31 N including grooved piece according our specification sheet HL.PDF.
WR 31 HS
Standard replacement straightening roll for resisting high speeds (above 20 m/s) according our specification sheet HS.PDF. HS 31 G including screw bolt and HS 31 N including grooved piece according our specification sheet HS.PDF.