Worked well, for a short while...
Really pleased to start with, cats got used to click noise quickly, and neighbour's cat couldn't get in. Batteries ran out after 4 months, but on replacing them the lock/unlock timer stopped working, so we manually set it morning and night. Batteries died VERY quickly with next two replacements, last replacement went straight to low battery, timer not working even on manual set. Only thing that still works is the microchip recognition. Had this 15 months and need to replace!