I got them from Dash4It, the map people.
They are Trekmates and are made from GoreTex, there is no specification i can find about which type of GoreTex it actually is but i will go as far as saying it's just like Paclite.
What i like about these is the breathability, the weight and the simplicity of design. I have no complaints at all. They do the job well.
To keep the weight down the underfoot retention is std bungee cord. The good thing is that it has a lifetime guarantee as do the gaiters. If the cord breaks you just email firstname.lastname@example.org for a replacement.
The weight specified is 105 grams per pair which is remarkable for a full length gaiter. However they must have done some tweaking because mine weight just 86 grams the pair.
They are all one size but are available in Male and Female versions.
If you are looking for a new pair then be quick, you can pick a pair up from Dash4it for £33.75 with Free postage instead of normal £45. Here.
Disclaimer. I bought these gaiters with my own money and have no affiliation with Dash4it in any way.