A note that might be of interest to bone people in Britain.....I was recently measuring some cattle skulls, and needed something with a bigger span than the usual human-sized craniometry callipers. As my large vernier calliper had been indefinitely 'borrowed' some while ago, I looked for a replacement on Ebay. A precision set of this size will cost £200-£350, but on Ebay a firm called Westcity Corporation have 24" aluminium Vernier callipers for £7 plus the same for postage. These are a bit rough round the edges and have a printed rather than engraved scale, but by a standard measure, accurate to 0.1% or less. A as one-time engineer, I wouldn't use these for high precision work, but for bones, and as a cheap item for the financially challenged, well worth the money.