I bought (well actually my brother in Australia) some 10mm FK hub centric spacers from yourself just before Xmas. I got them fitted on the 24 of December last year (2012) and I've just taken my rear wheels off to fit some 12mm hub centric spacers instead and to put the 10mm ones on the front, only to find out the hub centric part of the spacers have sheared off!! They've only been on 3weeks and 2days!!
I don't think this is expected is it?
I have pictures of he spacers on my phone if you wish to see them?