Attwood SL2405 Gas Spring 15" Extended, 9.5" Compressed, Blade Style, 40 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. Extended 15" Compressed 9.5" Stroke 5.5" Socket 10mm Blade Force 40 lbs. Rod 8mm Cylinder 18mm