Professional design: Designed for scuba diving tanks, this Diving Tank Refill Adapter efficiently transfers air from large to small bottles and includes a connecting hose with an 0.8 cm/0.31 inch interface. Benefit: enables simple air transfer and topping off without extra adapters, reducing setup time on site. Luminous gauge: The adapter features a luminous gauge that remains clearly visible underwater up to 80 meters, ensuring reliable pressure readings even in low light conditions. Benefit: you can monitor pressure accurately without supplemental lighting or headlamps. Quality material: Made entirely from 6061 aviation aluminum, the adapter offers waterproof performance, hardness, and durability under pressure. Benefit: robust, longlasting construction that withstands demanding diving environments and repeated use. Easy to read: The precision dial of the adapter is easy to read and provides MPa pressure values at a glance. Benefit: quick, accurate pressure checks to help prevent overfilling or underfilling. Key specifications: Interchange interface is 0.8 cm/0.31 inch to connect between large diving tanks and smaller bottles. Use scenarios: On a dive boat or at a site, use to refill small scuba tanks or pony bottles from a larger air cylinder, enabling buddy sharing and extended dives. During training or rescue simulations, off small cylinders from a larger supply to practice air management and response timing. In field equipment setup, quickly verify and adjust pressure on small bottles before underwater activities to ensure safe and reliable performance.