China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

After the specific lamp has been selected, the next step is to check the lamp’s mounting base. The lamps most commonly used in the hobby are single-ended, with a screw-type mounting base. The size of the base and the threads is also described by a code, although names are more commonly used. For example, Base - E39 is commonly called a mogul base. European lamps also have a mogul base, but it is slightly different from the E-39 and is called E40. The differences are small enough that the E40 base lamps will work fine in the typical E39 mogul base used in the U.S. Double-ended 150-watt lamps use the RSC (RX7s) base, while the 250-watt double-ended lamps use the Fc2 base. Figure 3 shows the various shapes and configurations of lamps and bases, along with the restrictions on their various operating positions.