Genuine Microflex curtain hooks. I say genuine, because various companies have copied the principle of these sew in adjustable curtain hooks. this is fine, and the alternative hooks work just as well. The issue of genuine arises when the hooks start to become brittle over time and need to be replaced. The hooks of alternative manufacturers aren’t compatible with the Microflex sleeves.
Mircroflex curtain hooks are available in various sizes:
Although at the time of writing, 2017 I am only able to source the 55 & 95mm sizes. However as most customers only buy this product to get the actual hooks, size is generally not important. Sadly I have never been able to source the hooks as a separate component.
Microflex were perhaps the first kids on the block with this sew in adjustable curtain hook design. They have been very popular especially on commercial installations such as hotels. So far as I remember they have been around at least since 2008.
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.