Although I haven't actually purchased any of these picks from Amazon, I have been using the Jim Dunlop Nylon picks for years. I prefer .38mm for simply strumming an acoustic, though I lean towards the. 60mm for almost everything else, but if I want a sharp, bright  sound I go with .88mm. rather than a full mm. because I still like to have that flex. Frankly, I don't know why one would use any other guitar picks than these.