General description The Laser Tools Water Pump Wrench is designed specifically for older GM (Vauxhall/Opel) engines, facilitating the adjustment of cambelt tension via the water pump. Technical specifications Size: 46mm x 1/2""D Compatible engines: 1.6L, 1.8L, and 2.0L Equivalent to OEM KM409A Material: Chrome Molybdenum Finish: Satin