EDELBROCK AFB METERING RODS 1 pair of metering rods for Edelbrock Performer Series, Thunder Series or Carter AFB Competition series. The first number is the higher part of the rod. The next number is the power tip of the rod. If there are 3 numbers in the rod size the middle number is part throttle size and usually found in the early model OE AFB carbs from the 1960-1970 era. Choose the size that you want from the drop down menu.