Attwood SL31305 Gas Spring 7.5" Extended, 5.25" Compressed, 30 lbs. Popular replacement gas springs. Made with bio-degradable, no hazard to water, grade oil (WGK), making them the marine industry's most environmentally friendly gas springs. All springs pass ASTM B117, Attwood salt spray and a 30,000 cycle lifecycle test. Mounting brackets available separately.