Aprilaire Model 500A By pass humidifier with Automatic digital control. Includes water panel, Outdoor temp sensor, saddle valve, 24V Transformer,built in damper. Unit is 15.62" wide x 13" Tall and 10.25" Deep, Plenum opening size 9.5" SQ Bypass duct diameter 6". Bypass connection comes mounted on left and can be modified for right side applications. Free freight on this item in the continental U.S.(UPS Ground) Items are new and unused in original box. Please  call (952) 884-8266 with questions call (612) 518-6683 After 5:00 and on weekends. I ship nationwide.  Minnesota residents will be charged sales tax.