Thick handles on your dumb bells and bars work your grip like nothing else. More info. and prices and bottom of page.
below are both a 3" and a 2 & 3/8" inch grip dumb bell
Dumb Bells can be made in different sizes from standard 1" bar  at 24" long so you can get a whole bunch of 10lbs. plates on, all the way up to olympic style bells with appx. grips of 2 3/8", 2 1/2", 3", and even 3 1/2". Grip width is 6".   The dumb bells range from $40.00 plus shipping up to $60.00 plus shipping for a pair of 3 1/2" grip bells. Alterations could be made if desired.   The larger sleeves can be welded onto the 2 3/8" grip or can be left loose giving you a rotating grip held in place be the weight plates.    Shipping will range from  appx. $15.00 to $30.00 depending on which bells and where you are located.