The 3/8" Sq. Drive Anvil Adapter (191A50-3) installs quickly and easily into Makita’s 12V max CXT® Lithium-Ion Cordless 3/8" / 1/4" Sq. Drive Ratchet (RW01, sold separately). When used with the RW01 and socket (sold separately), it is an efficient solution for loosening nuts and taking the nut off the bolt. It is made of high-quality materials for long life.