The Altura Thermocool has a seamless body construction. The seams, where they do exist, aren't quite invisible, but still help make this a very comfortable base layer. Its slim fit slips in easily underneath any type of jersey.
The fabric wicks incredibly well. On days that've turned out much warmer than expected we never ended up feeling overdressed and overheating. This is a good balance of a base layer that adds extra warmth when you need it, but can still deal effectively with a sudden rush of sweatiness.
Surprisingly for such a close-fitting style that consists of manmade fibres it doesn't actually smell too bad either. Even now. Where we usually draw the line at one ride with synthetics, we've stretched this unwashed layer out to two and not lost friends because of it.
The Thermocool gets extra marks for its generous length - even on a tall tester this is plenty long enough. It doesn't ride up to create chilly gaps, and stays firmly tucked in to your shorts when you need it to. There's no cold margin at the wrists either.
This is an excellent all-rounder that works across a range of uses, but that generous length means you're very well covered in even the raciest crouches.