Having mislaid my RED Spokey spoke key, I did the wheel build mentioned elsewhere with one of those Evans multi size keys. It did a good ish job, but the Spokey ones grip the nippul on three sides, giving less chance of rounding.
Thusly I went to town this lunchtime. First bike shop didn't have one, second one, very much a "proper" LBS, had a similar thing, made by Torque. Yes, it grips on three sides, yes it's RED. No, the manufacturers don't use a common colour code, so it's too big. Arse.
(The nice man in the shop did warn me I should measure the nippul first, but I ignored him)