The hinged shutter is magnetic to ensure its good closure and flexible so that your pet has no difficulty opening it. 4 sizes available (see details). The aluminum door is the most resistant model on the marke Small: 29.8 x 20.16cm / 24.5 x 15cm / 132mm / 7kg (E0272) Medium: 40 x 27.7cm / 34.8 x 22.5cm / 209mm / 18kg (E0273) Large: 50.2 x 32.9cm / 45.1 x 27.7cm / 260mm / 45kg (E0274) Extra-Large: 69.2 x 41.7cm / 64.2 x 36.6cm / 349mm / 100kg (E0275)