These replacement blades are made of tempered German steel and feature a long-lasting cutting edge. The MG100-0050 works with all Mobius & Ruppert desktop and hand sharpeners except models MG604-0020 and MG604-1252 (Stubby/Grenade Brass sharpeners in carded or openstock) which use MG100-6050 only. Ten blades per pack in a plastic box.