Durable design: Integrated stainless steel case and brass internals and connection are built for endurance and rugged conditions. The accuracy will not be affected by the outside and wet conditions, and it will not rust. Liquid Filled: It’s extremely critical to keep the needle steady during engine operation. Silicone oil ensures long-term work in low temperature(-40~140℉/-40~60℃) and suits for most outdoor conditions and seasons. Applicable : Suitable for Water, Oil, Air which is not corrosive to brass. Compatible With pool sand filter, air compressor, water tanks, home depot, RV, hot tub and etc.. Easy To Install: 2-1/2" Dial, 1/4" NPT lower mount Accuracy: +/-3-2-3% Measuring Range: 0-20 MPa/0-3000 Psi