PX-2 Size: Large (40.625" H x 16" W x 6" ) Features: -Pet door.-Collar operates for months on a single lithium battery.-Ultrasonic operation will not interfere with or be affected by other electronic devices.-Directional sensing system opens the door only when your pet is on a direct approach, not when wandering by, sitting or sleeping next to the door.-Dual range controls let you set independent inside and outside activation distances.-Automatic deadbolt lock.-Automatic safety retract system.-For cats and dogs up to 30 lbs.-Small Panel size: 8.25" x 10".-Large Panel size: 12.25" X 16".-If needed to mount to wall. The walll adapter tunnel is sold separately with HTQ1037. Includes: -3 Power modes: standard AC wall adapter (included), optional auto recharging battery backup protects against power outages (requires optional battery) and battery only (requires optional charger kit). Options: -Available in Small and Large sizes. Specifications: -4 way access control lets you select from In only, out only, full access or closed and locked. Dimensions: -Small Dimensions: 36" H x 6" W x 16" D.-Large Dimensions: 40.625" H x 6" W x 18" D.