TIMEWHEEL Professional JAXA Type XL Watch Case Back Opener Wrench for Large Waterproof Watches / Change Battery You Self - Distance between grooves: 55 mm - Steel Body with 3 adjustable Jaws - Three Prong Wrench - Wrench length: 6 1/2" inches - Case: 7 3/4" x 4 1/8" x 1 1/2"