I just got off the phone with Unimax. They will be up for sale on their site on Monday of next week. The Thunder has a 4mm stroke, which would be a better liner, less snagging. They changed the internal locking sleeve to ceramic to withstand the autoclaving process. No more grips seizing or locking up, all of the adjustable grips now come with this ceramic sleeve. There also is a non-adjustable grip for only $26, but it only comes in 19mm (3/4").
Check it out:
http://www.unimaxsupply.com/tatmch/1hawkspirit.htm