High performance magnetic latch system is operated by small magnetic collar keys (2 supplied). Helps reduce access by other cats. No batteries needed. Fits doors up to 5.4cm thick. Transparent flap with 4-way manual lock. Overall size (H)22.4, (W)22.4, (D)9.9cm. Door size (H)16.9, (W)16.9cm. Manufacturer's 3 year guarantee.