DMM Brass IMP
If you are pushing up through the grades and are finding placements for regular nuts a bit scarce then it could be time to get some I.M.P.s on your rack. They are brass micro wires which are great for narrow cracks. I.M.P. stands for Immaculate Marginal Protection and although these probably wont hold as the only gear on a massive fall, they can give great holding power if clustered and equalised.