Designed for professional diving operations, this overpressure relief valve (OPRV) SMB provides reliable protection and easy handling with high quality materials. - What it is: An overpressure relief valve for surface marker buoys (SMB), lifting cushions, and other buoys. Drawstring attached; simple assembly and use. - Function: Delivers diving-standard overpressure protection to prevent pressure release in lifting bags; portable and ready for field deployment. - Construction: ABS body, rubber disc, and corrosion-resistant steel spring for durability in harsh environments. - Handling: Ergonomic design supports comfortable operation and quick setup. - Portability: Compact, portable design suitable for on-boat and field use. - Compatibility: Compatible with SMBs, lifting cushions, and other diving buoyancy devices requiring overpressure protection. - Use scenarios: 1) Open-water dive operations to deploy a surface marker buoy and maintain pressure safety during deployment. 2) Salvage or lifting work using lifting cushions, ensuring safe pressure management while hoisting gear. 3) Training or remote field applications where reliable, portable buoyancy protection is needed.