The gauge will thread directly into a regulator’s first stage HP port With a complete kit, it will thread onto the end of a HP hose Kit includes gauge with rubber boot, in-line adapter and airspool Gauge and airspool include Viton O-rings Glow in the dark gauge faces Available in either imperial (PSI) or metric (BAR) units The Highland Mini Tech Gauge is a must have for technical divers. This compact gauge, measuring just 1.1 in (2.8 cm) in diameter and 0.88 in (2.2 cm) thick, is designed for mounting directly into a high pressure port of a first stage regulator or attaching to a high pressure hose with the included adapter and air spool. It's the perfect solution for stage bottles, decompression stops, and safety stops, eliminating the need for a full-size pressure gauge. With its bright white face, the gauge ensures easy readability even in low light conditions, making it a reliable companion on any dive.