Fuel systems that weep, plumbing fittings that drip, hydraulic lines that lose pressure — a failed O-ring is behind most of them, and you won't find out until you're on the job with a half-assembled fitting and no replacement. This 225-piece NBR rubber assortment covers the most common US-sized O-ring applications in one box: fuel, petroleum oils, water, and glycol. NBR (Nitrile) rubber is the standard for fuel and petroleum contact — it handles gasoline, diesel, hydraulic fluid, and LPG without the swelling and embrittlement that destroys natural rubber over time. The assortment organizes the most frequently used AS568 and metric sizes in a compartmentalized storage case so you can find the right ring without digging through a loose pile. 225 pieces covers the majority of O-ring callouts Stocked at Crofton Lumber and Akron Lumber.