A decent base layer is an essential. Bionicon’s uses super-fine 18.8 micron MAPP accredited Merino, so it’s good for the livestock that produce it and the environment, as well as being the highest quality wool.
The Raglan cut has no seams on the shoulders to interfere with riding packs and the cut is snug without being overly tight. Despite being made from fine material, it resists snagging well. The added benefit of Merino is the lack of funk after wearing a few times between washes.