Mechanical oil pressure gauges are found on this page. Each oil pressure gauge is designed to withstand the most demanding heavy duty applications found on diesel engines such as Detroit Diesel or marine transmissions such as Twin Disc. Below you will find the two types of oil pressure gauges. Engine oil pressure gauge from 0 to 100 psi and marine transmission oil pressure gauge from 0 to 400 psi. All our mechanical oil pressure gauges come with a 100% money back guarantee and 24hr worldwide shipping direct to you.