The Ametek/US Gauge 155206 is a 1901 SOLFRUNT Series process gauge with a 30 psi pressure max, 4.5" dial size, 1/4" NPT lower mount connection, brass wetted material, and aluminum case material. The Models 1901 and 1931 4.5" process gauges have an aluminum back-flanged case for applications needing stem or wall mounting. These models are available with wetted surface material in brass/phosphor bronze or 316L stainless steel. They are available dry or liquid filled from the factory or your local stocking distributors, or can be ordered with a liquid fill kit for filling in the field.Span adjustments can be accomplished from rear of case without disturbing the gauge internals. Pointer adjustments are easily made by removing ring and window.