An older lady of my acquaintance is looking for a door-flap for her microchipped cat to exclude a neighbourhood cat. The new flap will replace an existing dumb door-flap. Any recommendations or traps for the unwary player (size incompatibilities?) or just order something at random?
Happy Sureflap-ee here – we are on our second, the first did die, but I reckon we're into the third decade of using them and they get some use and abuse. Check the size, the details are on the websites, and there are various attachments to make adjustments. Also check the cat fits through, some cats are chunkier than others. We had holes cut to size for both our installations (the first through a double-glazed French door unit, the current one through a UPVC panel, hence the factor of 10 price differential – the glazier wasn't happy to notice a small crack once he'd finished installing the floor-to-ceiling French door unit but kudos to him for fessing up and making a new one).
Our cats were wary at first, but a bit of manual encouragement seemed to have got them over the issue.