"The 500 Cat Flap from Staywell is a 4 way locking infra-red flap suitable for cats up to 15lbs. Finished in white, the 500 is suitable for fitting in windows, walls and doors. The 4 way locking action allows you to set the flap to In Only, Out Only, Open or Locked, while the infra-red collar key will further ensure stray cats are kept out. The Staywell 500 comes complete with a colour coded key. If you purchase additional keys, you must make sure they are of the same colour as the code on the flap. Overall size – 241mm x 252mm, Maximum pet shoulder width – 150mm."