A pneumatic fastening tool may include a tool housing including a dispensing portion for dispensing a fastener, a handle portion and an inlet configured to receive input of compressed air. A cap assembly may include a cap housing having an opening and mounted to the tool housing. A deflector may be configured to direct exhausted air through an outlet in a first direction. The deflector may have a stem received in the opening. The stem may define a bore extending in a second direction that is distinct from the first direction. A locking member may extend at least partially in the bore and be configured to rotatably capture the deflector relative to the cap housing.