ToPicks 4PCS Window Restrictor Hook 304 Stainless Steel Child Lock Restrictor Safety Catch with Screws for UPVC Window (2PCS Left+2PCS Right)

OK... Great in theory, I have one from another manufacturer which is brilliant.However, for some reason these have a bend on the end of the long piece, which is unnecessary, worse though, the peg part it slots on, is too long to fit any of my double glazed units. I can't close the window with it installed, and it's not adjustable.

Not easy to fit but that is just down to the fact that you need to fit one part by screwing it in from beneath the window which is awkward. I’m not totally convinced they are fully effective. I was still a bit worried that the catch would not work reliably but I bent it a little and that seemed to improve things.

Would have rated higher potentially if I'd actually fitted them! Comes with no instructions, no guide for fitting.

Didn’t actually fit my own windows , but we’re great on my sons house