They are similar in construction like the Quarz' on my Verlicchi, but fitted lower in the line up.
Got my hands on a FUNK specced with New Success (top of the line, predecessor of the Quarz) while ago. The cantis were similar to the Quarz ones. On the FUNK the former owner substantially overtightened the bolts that hold the pad, causing the aluminum parts and the canti itself to crack. Design not as foolproof as say XTII.
The black aluminum bit that sits with a very narrow gap next to the bolt that hold the canti (and with which you adjust springtension) can touch the canti, for example after slight deformation caused by overthightning. This will influence the brakes performance and/or adjustability. In this case you will have to add an washer between bit and canti and problem is solved.
Not just bike shop staff either. Down my way I've been looking for some of these for months. I've asked in all the local shops (even the least likely ones) and it's as if they don't exist! I've even looked on the bay and all I could find was a guy selling an assortment of sizes (of which only 1 or 2 would be usable) for about £15!
I've looked at the ones used on many BMX U-brakes but they're just too large.
It's irritating as I've got a set of Crystal Design Vs that are waiting to be fitted to my Saracen but I'm missing 1 of these things. :evil:
i used to order loads from hykeham wholesale . they wernt the greatest quality and used a small screw instead of a grub screw but my mate used a few on his kitcar throttle without a problem