Castrol Braycote™ 646 流体润滑脂is a light tan, homogeneous, semi-fluid, lithium stearate thickened synthetic grease. Additives have been employed to impart resistance to oxidation, wear and rusting.

Braycote 646 is intended for use in the operation of the M16, M61, M39 and related types of automatic weapons under thin film lubricating conditions of extreme pressure. It is a suitable lubricant for small gearboxes, where light starting torque is a factor and for such applications where it is necessary to pump the grease to the lubrication area through extremely small orifices. Braycote 646 may soften certain paints and adversely affect natural rubber. Paints and rubber suitable for use with this lubricant are readily available.