A locking mechanism for securing different expansion cards in a slot of a chassis of a computing device is disclosed. The locking mechanism includes a base and a main body. The base is coupled to the chassis and movable between an open position and a closed position. The main body is coupled to the base and movable between a first orientation and a second orientation. When the base is in the closed position and the main body is in the first orientation, a first mating feature of the main body engages an expansion card having a first form factor inserted into the slot. When the base is in the closed position and the main body is in the second orientation, the second mating feature engages an expansion card having a second form factor inserted into the slot of the chassis.