Regal tip offers butt end sticks that are .570 diam. This is just under the 5A(.580), & it is a solid stick without a super heavy feel.
Nice balance, and rolls come out smooth with little effort.
Zildjian offers a DB stick that's more like a 5B and it feels heavier at the 'tip' area than the Regal. It's only a little bigger diam. at .590, but to me it feels a lot heavier overall.
The durability is good on both brands.
Very solid sound on drums and ride, crashes are about the same if you mostly strike cymbals with the shaft and not the tip.
Pro-Mark offers a DB, and I think the diam is .555
It's a nice stick if you like a smaller diam in the grip. Still a solid sound on everything.
Going through all three brands, I like the Regal the best. All 3 brands were straight, but Regal had a better consistency in feel over PM, and Zildjian had some severe weight issues over the 12 pair I bought.
The PM sticks just seemed to break in the middle sooner than Regal and Zildjian too.
Alex Van Halen used the Regal Power rock sticks for a few Van Halen tours and they were the sticks he used on the Right Here, Right Now DVD.
If these diameters aren't what you're after, you can get them made custom from customdrumsticks.biz
They make awesome feeling, reliable, sturdy sticks at a great price. I've had them making my sticks for about a year, & I wouldn't go with any other sticks now.
Hope this helps