Leashes for Leashless Tools

Do any of the climbing companies manufacture those extendable (key-chain style) leashes I've seen people using for leashless tools on longer routes/in the mountains? Or are they made for some other purpose and then adapted for this use? Have you used them much and what do you think?

http://www.mountaingear.com/pages/product/product.asp/imanf/Black+Diamond/idesc/Spinner+Leash/Store/MG/item/217489/N/0

just found these but would still like to know of any others and what people think of them -

Grivel also makes them: rockandsnow.com/store/produ…

The Grivel leashes are a little short. I wish they were under a little less tension when my arms are fully extended. Haven't tried the BD version.

I just made a pair for less than $15. The local hardware store had everything I needed. Sure, its not as light, compact and fancy as the BD ones, but I'd say for saving 35 bucks, worth it.

They are usually called umbilicals.

Been climbing on my home-made ones for a couple seasons now and they work fine.

alpinedave.com/leashless_ri…

The new BD "Spinner" leashes have a rotating swivel, that reduces tangles - that is the HUGE advantage over the Grivel ones. I'm going into my second season with my pair and they're holding up very well.