The 49-66-6740 Milwaukee 3/8'' Drive Socket Rail Clips are interchangeable for rail customizations based on your socket storage needs. Our 49-66-6740 Milwaukee 3/8'' Drive Socket Rail Clips work with all chrome and impact sockets and are offered in 1/4'', 3/8'', and 1/2'' drive. Removeable end caps make the rail adjustments easy. The Milwaukee® Rail Clip 10 Packs are available in 1/4'' drive (49-66-6739), 3/8'' drive (49-66-6740), and 1/2'' drive (49-66-6741).