Tacx Thru Axle for Giant TCR
The specs of the thru-axle that you need are here. The one that you need is T1707, which is 12×142 with a thread of M12×1.

The T1707 and the T1711 both fit a 142×12 mm with a thread of M12×1. The T1707 has an axle length of 162.5 mm, while the T1711 has an axle length of 175 mm. I couldn't find the TCR specs for this online, but since I ride a Giant Propel Disc, which has the same thru-axles as a TCR, I was able to take mine out of my bike to measure it. I found that it measured 162.5 mm (see photo). This means that the T1707 is the correct axle.