Used by tri champions, most UCI teams, etc etc. See https://corebodytemp.com/ for info.
Mine is perfect and was used for a season. I’m selling because I won’t be doing a real “heat destination” race (or drilling down on heat management to this extent this thing allows) for the next few years. As a Highly Heat Sensitive Person, the Core is the best and most useful piece of tri tech I have owned. If were a coach who had 10 athletes going to a hot weather race, I would make sure I had 11 of these to lend out.
$200 shipped in the US or Canada. I would consider renting to an established forum member for their build period to Kona; PM to discuss.