extrema ratio bd1 r kiseninis peilis n690 plienasThe Extrema Ratio BD1 R is a new pocket knife with a lightweight blade. It features a very slim profile with a focus on lightness, but without sacrificing the strength and reliability of the regular Extrema Ratio model, as well as a black anodized Anticorodal handle. A modified spearhead, satin blade is made from Bohler N690 steel, hardened to 58 HRC, 70mm long, 2. 5mm thick, with a simple sharpening and artificial edge on the first third of the back.