I really rely on my umbilicals. As much as they are a moving belay for me I also have come to rely on them to retain my tools while climbing leashless. On the occasions I do climb without umbilicals I am very careful to watch where my tools are all the time and that they are securely placed. And I don't worry about my partners kicking or bumping them off the climb. May be I should be more concerned all the time..

more here:
http://coldthistle.blogspot.com/2011/01/umbilicalssomething-to-think-about-and.html

spinner leash(bought or made), cut binner out install small mallion.

They freeze up..good idea if you never want to move the umbilical on your tool.

dont freeze up bad enough you cant break it free. unscrew and move

I've had the little biner on my spinners work itself loose a few times. Haven't sorted out a decent solution yet...

I've dropped my tool with the BD umbilicals a couple of times. Used a homemade system before the commercial product came out with small biners. With the new mini metolious biners the problem of having something clunky swinging around is solved. I think I'm going to go back to the homemade solution which is more secure and stronger too.

I made mine a few years ago using this beta before the commercial options were available: http://www.alpinedave.com/leashless_rig.htm.

I'd still build my own again today because it seems like the commercial devices are making this more complicated that required. Remember that you're building a simple backup for dropping a tool, not a NASA moon-landing. So keep it simple and don't bother with the heavy spinner unless you do some really funky swapping of tools. If you're weight conscious then get yourself a superlight mini locker for the belay loop end and 2x mini Metolius biners.

That's it... works great and is strong, light, and cheap!

I dremeled the steel biners on my BD spinner off and replaced them with nano 23's. More sensible weight to carry as I could use them if I had to, but I've also taken to clipping the rope in at the really stressful stances I get myself into.

If I were to do it again I would build my own as per the link in Anton's post. The BD ones are a little too long for me, if I ever actually fell I'd have a hell of a time getting up to my tool(s). I always sink one super high and one at or below eye level to combat that, but still.

more:

http://coldthistle.blogspot.com/2011/01/umbilical-attachment-points-again.html

Interesting discussion. I've been using home-made umbilicals for some 15 years. I take a length of 6 mm cord that's a little more in length than twice the distance between my belt and my hand when I stretch my arm upward. I tie the ends of the cord together to make a loop. I then girth-hitch the loop through the eye on the spike of my tool, tie 2 or 3 overhand knots in the loop that now emanates from the eye at roughly equal intervals (this keeps the two sides of the loop together and permits final adjustment of the length). I then clip the far end of the loop into a biner on the belt of my harness. Ditto for the other tool. I tried clipping both umbilicals to the same biner, but prefer to have a separate biner to the right and left of center on my harness to permit the umbilical to travel straight up to each tool instead of diagonally across my chest from a single centered biner. The girth hitch gets in the way when I need the tool for caning through snow or low-angled ice, but it can be removed without too much difficulty. I find this is preferable to swinging tools with clunky biners attached to the spike.
Tom B.