The E-Image 100mm Ball to Flat Base Adapter is designed to adapt flat base tripod heads to fit tripods and hi-hats that have 100mm bowls. It features a standard 3/8"-16 screw and includes a bottom wing nut tie-down for leveling. In addition to flat base tripod heads, the adapter can also be used to attach other accessories that have 3/8"-16 female threads, such as a slider, to 100mm bowls.