I've got a Turnigy Ultimate 7500 battery that weighs a little over 310 grams. It performs well but I'm looking for something a bit lighter, in the sub 250g range, as my ancient chassis are already overweight and unbalanced. It seems the lower capacity Turnigy batteries don't really save much weight, they're still around 290-300g. What popular options are out there that don't sacrifice much? I'll be running it in either a 21.5 or 17.5 blinky class.