This listing is for a set of two Arnold replacement primer bulbs, model number 490-239-0002, designed for use with gas-powered lawn mowers made by Briggs Stratton. The bulbs are made from durable plastic and rubber materials, ensuring long-lasting performance and reliability. These prime bulbs are specifically designed to fit lawn mowers in need of replacement parts, ensuring that your lawn remains neat and well-maintained. The power source for these bulbs is gas, making them an ideal choice for those who prefer to keep their lawns looking their best.