The G-Lock includes a one-way expulsion valve to provide suction suspension as well as a standard pin locking mechanism with pin seal. The lock allows a user to secure the locking pin in place at the nearest groove. With this unique design, amputees receive the security of a pin while minimizing pistoning through the use of suction. With its drop-in design, the G-Lock is CAD-friendly yet also easy to work with in traditional fabrication processes. For use in laminated or thermoplastic sockets, the G-Lock is easy to fabricate, allows for one-step lamination, and has a four-hole pattern for attachment to the socket. The G-Lock comes with one 38 mm pin. A tooling kit is required for use with the G-Lock.