Microflex curtain hooks 75mm. Microflex were perhaps the first kids on the block as it were when it comes to these very popular adjustable sew in curtain hooks. So far as I remember they have been around at least since 2008.
Many other manufacturers have now followed suit with their own versions. If you intend to use the complete unit, what I would call hook and sleeve then it probable doesn’t matter which version you use and personally I like the Vakoflex version. However if you only intend to replace the actual hooks then you need to be sure you are replacing like with like as then aren’t compatible with each other i.e. you can’t put the Vakoflex hooks onto the Microflex sleeves and vice versa.
Check out my page on Adjustable Sew-in Curtain Hooks.
The microflex hooks have 2000 stamped on them, and the part that is sewn into the curtain has the Microflex logo and the numerals 2000 stamped onto it.