1 Brian Johnson 6 years ago I thought it appropriate to add that Pyramid offers both the hex core and round core options in flatwounds. As said, the round core is a vintage style, offering sustain and is an exact match to their Selmer/Hofner Beatle string offered in the '60s. The hex core is performance flat string that is a bit stiffer but lasts longer, as it's less prone to unravel. Choice is good. Pyramid Strings is about the only company that is giving you all the options (IMHO). That's why I deal them.