Product type: Overpressure/pressure relief valve (OPRV) for BCDs, SMBs, lift bags and other inflatable buoys. Condition and construction: 100% . Durable ABS plastic body, rubber washer seal, and steel spring — materials chosen to resist seawater immersion and repeated use. Primary function: Automatically relieves excess pressure to prevent overinflation and rupture, and provides a fast, controlled way to vent air when needed. Key benefits: Safety: Prevents dangerous overpressurization of BCDs, SMBs and lift bags so you can focus on diving tasks instead of equipment failure. Control: Allows rapid, userdirected deflation to finetune buoyancy or collapse a marker/buoy quickly. Durability and corrosion resistance: ABS, rubber, and steel components withstand saltwater exposure and regular handling. Portability and ease of use: Lightweight and compact; supplied with an attached drawstring lanyard for secure placement and simple assembly. Compatibility and performance: Designed for scubastandard inflatables: BCDs (buoyancy control devices), SMBs (surface marker buoys), lift bags and similar buoys. Fits standard inflation ports and installs easily; springloaded relief mechanism opens under excess internal pressure and closes to maintain inflation under normal conditions. Typical applications / use scenarios: 1. Scuba diving with a BCD: Install the valve on the BCD inflator or auxiliary inflation point to prevent accidental overinflation during surface or descent, reducing the risk of uncontrolled ascent. 2. Deploying a surface marker buoy (SMB): Use the valve on the SMB to allow quick venting for controlled collapse when retrieving the SMB through a small exit or when adjusting buoyancy on the surface. 3. Recovering objects with a lift bag: Fit the valve to a lift bag to protect the bag from bursting during inflation and to vent air quickly and safely while lowering or securing a load. What you get: A readytoinstall overpressure relief valve with drawstring lanyard; simple assembly and operation without special tools. Notes for users: Compatible with standard scuba inflator fittings; inspect seals and spring periodically for wear and rinse with fresh water after saltwater exposure to maximize service life.