SS 91 is a high performance medium viscosity mineral cutting oil. Locks SS 91 is fortified with chlorine, free sulphur, fatty oil and special additives. Due to the high quantity of additives and their carefully balanced composition, Locks SS 91 is successfully used in extremely difficult working conditions, such as high speed turning, threading, broaching, drilling, gear hobbing and shearing for difficult to machine materials including stainless steel and heat resisting steels.