44" x 1/2" 2mil Kapton, spliceless on my Galibier. If you're looking for an alternative, the Origin Live (1168mm) belt is well worth trying as well, despite the fact that it appears to be rubber. It has a much lower modulus of elasticity than a typical rubber belt, and I find it to quite good sounding.
What Type Belt Are You Using
So which type of belt are you using on you TT? I am just curious as to what others use on their rigs? I am using a 1/2" Mylar belt on my Redpoint Model D... I make them myself from a roll of Mylar Streamers which is about to be gone, so I am sorta looking around for a replacement for the stuff I am using???