The 9916-M stainless steel clamping fork is unique because the cap-head screw is held captive in the slot of the fork so that it can't fall out. Think about how many times and how much time you have spent looking for the exact screw to clamp the forks in your experiment - you will quickly understand the value these forks provide. 9916-M clamping fork has a 25.4 mm standard slot to provide complete positioning range.