Jones Stephens' 30 PSI Liquid Filled Pressure Gauge has a 1/4" bottom connection, durable steel case construction, and a 2-1/2" glass face. This gauge features PSI indicators up to 300 PSI and is glycerin filled to absorb vibration for a concise reading. Designed for use with air, water, oil, and gas, Jones Stephens pressure gauges are manufactured of the highest quality materials to be durable and reliable.