Bostitch o-ring 149842. Brand new, OEM part.
I offer combined shipping, to do this, please add all items to your cart (instead of buy it now), and then click on your cart. Click "request total from seller" and I will send you an invoice with your total for all items plus only one shipping charge (whichever item has the highest amount is the total shipping you will pay).
If you do accidentally pay me more than one shipping charge when ordering more than one item, I will automatically refund the excess shipping when I ship your items.