Universal Marshall Instruments makes the most reliable fuel gauge in the industry. That is why we contacted them to make us an all black gauge with K-Tuned logo on the bezel. The Marshall Liquid Filled Shock Proof gauge accurately reads 0 – 100 psi of fuel pressure. The gauges are liquid filled to keep the needle firmly in place while the engine is running. Unlike cheap gauges where the needle is constantly boucing around. They are also shock proof so they won’t fail due to the vibration and constant movement of the engine.