One kit contains 12 screwdriver holders. However, add more as needed. Kit also includes 8 spacers for extra room. Each organizer has a magnet in its base. 10 lbs magnetic pull per organizer magnet. Organizer dimensions appx: 1.5"H, 1"W, 3/4"L. Any size tool, any order, large or small. Shape of design secures tools, not magnets. Tools sold separately.