Remember, it's the little things in life that count. Don't let a $0.40 O-ring ruin a $4,000 vacation. Nothing stops a dive faster than a bad O-ring.This O-Ring Kit of most common O-rings, has replacement rings for most tank valves, regulators and high & low-pressure hoses. O-Rings come in rubber, Viton, and silicone with 10 pieces each of 7 styles of rubber O-rings, 5 pieces each of 7 styles of Viton O-rings and 5 pieces each of 2 styles of silicone O-rings. Use rubber and silicone for air diving uses and Viton O-rings for enriched air nitrox. Make sure to include this handy plastic boxed kit O-ring in your save-a-dive-kit for complete preparedness. The dive you save may be your own!