Lux A772001T-005 BB2001-005 Medium Locking Thermostat Fits thermostats no larger than 5.25W x 4.50H x 3.0D Medium size  External Dimensions 6.5W x 5.875H x 3.25D Limits unwanted access; Tamper resistant, strong durable plastic One Key and mounting screws included Larger Guard available See Model BB3001