Overpressure relief device (OPRV) for buoyant systems including BCDs, surface marker buoys (SMB), lift bags and other buoys. Attaches with a drawstring for quick assembly and easy operation. Materials and construction - ABS body with rubber washer and a corrosion resistant steel spring - Designed to withstand saltwater immersion and repeated use Design and suitability - Specifically designed for scientific and professional equipment and materials - Built for reliable performance and comfortable handling in field conditions Function and performance - Allows rapid air release as needed to prevent accidental overinflation during inflation - Enables you to focus on diving tasks without constant worry about buoyancy overpressure 2-3 practical use scenarios - Deploying an SMB or lift bag: vent air quickly to maintain stable buoyancy while positioning or deploying equipment - Field scientific diving: manage buoyancy of buoys and related gear during data collection and equipment setup - Routine BCD inflation management: use drawstring attachment to quickly connect and regulate air release during pre-dive checks or ascent planning Benefits at a glance - Improves buoyancy control and safety by preventing overinflation - Simple, fast setup with a drawstring attachment - Saltwater resistant materials for durable field use - Suitable for BCDs, SMBs, lift bags and other buoyant devices in professional applications