Herdim Opening Chisel, 23mm Using this tool makes opening of the instrument an easy task. Tapered blade can be easily bounced with hammer on the thicker (2 mm) end, very thin blade 0.4 mm easily opens the plate-rib joint. The corner and endblocks can be gently opened from the inside of the instrument, which reduces the danger of cracks and snaps. The cutting edge is slightly curved and beveled on both sides. Hardness 59 HRC, stainless.