UKH

Yonks ago I bought some ball nuts as I had aspirations on a route on which one was useful. However I never ever used them and they have languished unused in a dim and dark corner of the garage. Does anyone find them useful and should I start carrying them instead of microcams or should I return them to their dim and dark corner?

The two smallest go smaller than any micro cam. 

I quite like them. They go in those thin breaks that people would smash knifeblades into. 

The larger ones have limited use vs small cams.

The smallest one goes in parallel sided cracks that you torque picks into on winter mixed - the only reliable protection for that situation IMHO

Like you I bought some small ones in fit of madness ages ago, as my rack is allready massive I never end up carrying them as there too niche. Possibly if I was into headpointing/pre inspection of gear/harder routes I might, but alas as I'm a massive punter I'm not into these things and they lurk on my 'reserve rack' destined never to leave the back of the gear cupboard 

I used one a couple of times at Swanage, they slotted in nicely underneath rusty pegs that had been banged into a thin crack. Very reassuring to have them as backup to the peg.

As above I have the smallest two sizes. For the size/weight of them I routinely carry them on anything that's not definitely within my grade. They usually don't get used but it's one of those "when you need them, you need them". They go places that there's no real alternative 

They are certainly useful in some placements and they will hold a heavy fall but they take some getting out afterwards.

Some ball nut testing here: youtube.com/watch?v=qkyIEv7gSaQ&

I've got 2 sliding nuts:

• A Faces one, which has a micro cam-style slider in a captive groove on the main nut.
• An HB brass one, which is just a wedge sliding in a groove on the main brass body.

One of them is called a Slug, but can't remember which one!

I've definitely carried them, pretty sure I've placed them at least once, but never fallen on either.

My mate Christian has three.  Useful where micro-cams are too big.