Is there a US company that sells these things? I would prefer to buy in the USA if possible. I would like to try these out. Thanks.
i have no idea who if anybody makes them in the USA. 
do a google search or make them.
it doesnt appear to be too hard to make. 
i merely presented the link for an idea, not to make people purchase them
My tippet spools come with these on them and when the spool is empty I keep the keeper.
Right now with a fly tying spool of red wire I wish I had something like this because it wants to uncoil while in use, would love a smaller version of the ones that I get with my Rio tippet.
what fly tying threads come with them?? uni doesnt, danville doesnt