The BE 85.305.001 is a vital diagnostic accessory designed to provide instant and accurate pressure readings for any high-pressure system. The kit features a large, 2.5-inch glycerin-filled gauge mounted onto a 3/8" quick-connect manifold. This "inline" design allows you to snap the gauge directly onto the pump outlet and then attach your hose to the gauge's outlet, giving you a live reading of the pump's performance. The glycerin filling stabilizes the needle against engine vibration and pressure pulsations, ensuring a steady, readable measurement and extending the life of the internal mechanism.