The accelerator pump nozzle is made of brass, which is corrosion-resistant and is processed by a high-precision CNC lathe from Japan with precise dimensions.Easy to replace, the copper gasket is durable and long-lasting. One order contains four of this product, with default sizes of 0.025", 0.028", 0.032", and 0.035" each. Includes 8 copper gaskets. If you need different size combinations, please click on 'Contact Seller' after placing your order and leave us a message telling us the size you need. Thank you!Size range available for ordering: 0.020-0.080 inches Straight jets For 2300/4150/4160/4500 carburetors Vintage improved brass Holley acceleration pump jet Made of brass material, with excellent quality and precise dimensions. 0.025" 1pcs,0.028" 1pcs ,0.032" 1pcs,0.035" 1pcs Size range available for ordering: 0.020-0.080 inches