Grivel and BD both offer a decent leash system. My problem is that they are "systems". I have been using a old style Grivel leash that I've had for 5 plus years now. On occasion I've ventured out with the newest BD Spinner leash, till it proved itself unreliable. But I own them all, Grivel and BD versions and have used prototypes that still aren't available.
I'm not much into fancy stuff when simple will work, as well or better.
Do a search for umbilicals on the blog here and see what is currently available. I'll do another comparison soon.
I bought and had a chance to use a pair of the Blue Ice Boa leashes while I was here in Chamonix. Liked them enough I have set my old Grivel's aside and am using the Boa now full time.
I like they pull test @ 550 daN or 1236 lbf. No one else committing to over 800 lbs. BD says 800# but the UIAA test is 450# which is what the BD and Grivel is rated at, so why bother?
Because in climbing gear, more weight, "more better" (strength wise) generally.
More info here:
Now available in NA here:
Soloing on the Passarelle gully, N Face of the Midi with a Boa leash system hitched to my harness and tools.
I'll leave it to you imagination on where the ice really comes from for the start of this climb. Fun climb in cold conditions, none the less.
I went right and avoided the ladder, the crux stick on that exit being a very old wood cement form. But I did stop for a quick nap on the opposite viewing platform and lunch before heading off to ski the rest of the day. Colin on the same climb a few weeks later. Only in Chamonix!
Boa leash and a Cold Thistle hammer on your Nomic...what more could you need?