TJ also looks to be using a custom BTA bottle. The thing appears to be refillable, and has a straw. It probably functions similarly to the Speedfil A2, although I think its refill mechanism is a little more rudimentary (pop lid off, fill bottle, replace lid).
TriRig has already showcased two large galleries from the Lonestar 70.3 in Galveston, Texas. But as usual, some of the most interesting stories about gear are hidden in the fine details. So I went back into our image files and dug up some of the small bits and pieces that I thought were particularly noteworthy and blew them up for you to see firsthand.