These Main Jets, sized at 0.045 inches, are designed to fit Stromberg 97, 81, 48, 40, LZ, and other applicable models. The set includes two jets that play a crucial role in regulating the fuel flow within the carburetor, ensuring an optimal air-fuel mixture and engine performance. Installing these jets is simple with the Genuine Stromberg jet wrench (9071K), providing a secure and accurate fit. Selecting the appropriate jet size is essential for achieving the desired fuel mixture for your specific carburetor and engine requirements.