The petsfe Staywell Original 2 Way Pet Door offers a 2 6Way Locking system, allowing owners to adjust their petsboundaries, giving more freedom to petsand control to Owners. Giving your petsthe independence to come and go as they please, the Door can be set to unlocked, but when boundaries need to be established, locking the Flap will restrict your petsmovements. With the provided cutting template and easy installation guide, fitting the Original 2 Way Pet Door into most applications is Fast, precise and hassle free. Important Information Optional tunnel extension (suitable for most door thicknesses) is included with the Medium and Large sizes, but is an additional purchase for the Small size. Small For petsup to 7 kg Frame dimensions: 236 mm x 196 mm Flap Size: 175 mm x 152 mm Cut out size: 185mm x 158mm Medium For petsup to 18 kg The size of the frame is 352 mm x 292 mm The Flap dimensions are 238 mm x 218 mm Cut out size: 281mm x 237mm Large For petsup to 45 kg The size of the frame is 454 mm x 383 mm The Flap dimensions are 325 mm x 289 mm Cut out size: 370mm x 314mm What?s in the box 1 X petsfe Staywell Original 2 Way Pet Door 1 X Installation Guide 1 X Operating Guide 1 X Cutting Template If you have any questions please contact the petsfe customer service team on 0800 046 1414. Safety Warning Suitable for medium size dogsup to 18 kg