ok the outer bulbs are h4 and are low beams, the inner bulbs are h1 and are high beams. definetly only one of the filaments of the h4 is used. the h1's are very bright... yes the actual bulb size is small. I guarantee you they are brighter then the h4's. i hope you realize you will be blinding everyone if you set it up so the inner light is on with corner lights. the headlight your uncle gave you was the one that was tampered with.