The poppet O-ring is a critical sealing component in the Bostitch MIIIFS flooring stapler, ensuring an airtight seal for the poppet mechanism. Over time, this rubber O-ring can degrade, shrink, or crack, leading to air leaks and reduced tool performance. The correct replacement poppet O-ring for the Bostitch MIIIFS is part number BOS121799 (also referenced as NB75 or #75 Poppet O-Ring). This O-ring fits the poppet assembly (part #121800) and has dimensions of 1.287" x 0.210".
Model: #121799