Superior Parts SP 120075 Piston Driver Assembly without O-Ring for Bostitch BT200 Replaces Bostitch 120075. Aluminum is crimped into the Unilok grooves of the shaft to prevent unscrewing. Our patent-pending UNILOK piston/driver is guaranteed to never unscrew our Aftermarket Piston Driver Assemblies. This Driver comes without O-Ring. Features: Compatible with: Bostitch Details Compatible with: Bostitch BT200 Industrial Oil-Free Brad Nailer More Information Model# SP 120075 UPC 099461760189 WARNING California Proposition 65 Brand Superior Parts