NLGI 2 silicone grease For all Hill hand pumps 40 grams Never use petroleum-based products on your hand pump. Use only silicone grease. Hill's silicone grease is NLGI 2, which is ideal for keeping your hand pump in good working condition. It's geared specifically toward the temperatures your pump will reach during pumping. Make sure you do not over-lubricate your pump. Follow the maintenance directions in the owner's manual.