Hsieh Hsu Products like: HSIEH HSU Knife - HSIEH HSU N.C. slitter single knife blade - OD 270 x ID 168,3 x 1,2, etc. HSIEH HSU Knife - HSIEH HSU N.C. slitter single knife blade - OD 270 x ID 168,3 x 1,2 1