An electrosurgical instrument is provided having a treatment portion attached at a distal end thereof and a handle for actuating the treatment portion. The instrument includes at least one switch, each configured to close an associated open circuit upon activation thereof for controlling at least one respective function or parameter associated with the treatment portion. The instrument is provided with a cap configured to mechanically engage the housing and having an inner surface including a corresponding number of mechanical interfaces configured to align with each switch, such that an activation force against an outer surface of the cap and relative to the housing closes the open circuit associated with a corresponding switch.