My understanding it is a standard measure. I buy felts 120gr, 140, 150, 160, 210gr. There is a progression of density/weight to each of the felts. I make a 'summer' weight felt out of the 120gr felts and it is a very light weight felt and needs to be stiffened to give it any structural integrity. So the 160gr will be somewhat lighter/less dense felt but I also suspect the diff between 160 & 210gr will not be noticeable by the wearer on a hot summer's day.
Check with Garrahan Hats up in LA. A bit of a drive but check with them and they may be able to direct you to someone closer to you. Perhaps even a millinery shop selling/making ladies hats can do a sweat band.
John Lofgren Monkey Boots Shinki Horsebuttt - $1,136 The classic monkey boot silhouette in an incredibly rich Shinki russet horse leather. 
Grant Stone Diesel Boot Dark Olive Chromexcel - $395 Goodyear welted, Horween Chromexcel, classic good looks. 
Schott 568 Vandals Jacket - $1,250 The classic Perfecto motorcycle jacket, in a very special limited-edition Schott double rider style.
Yes, I think if I remember correctly (not a safe bet) they bought Paul's Hats, but the group of females has split up and last I heard just 1 remaining member was running the shop.
either they didn't get along or the shop could not generate enough income to support the 3 of them or they discovered making hats is a tough way to earn a living..
as my dear departed mother would often say.....to me....."Even a blind pig finds an acorn once in a while"
