Keeps other pets outsidewith collar magnet for access permissiontransparent flap, silent actionwith special sealing and magnetic lockincl. Tunnel elementdepth 10–35 mmcan be extended with more tunnel elementstotal measurements 21. 1 × 24. 4 cmcut out size 16. 5 × 21. 6 cmflap size 14. 7 × 15. 8 cmbattery-operated (9 v battery not included)