These are good guards, v easy to fit and look smart too. Agree on sizing - I run 40mm MSOs with a v slight knobble and couldn't fit anything wider in. One slight point: the rear bridge clip snapped on mine after not much use - these are plastic rather than the usual metal clips - but I managed to source a metal replacement from SJS, so job jobbed.
P.s. I believe SKS have released a 56mm version since I bought mine, but not sure if they're available over here yet