The AT/C Racepant is a more durable, lightweight option for runners looking for pants that still have high levels of waterproofing and breathability. High performance is still the key here.
Inov8 says:
A versatile, fully featured unisex trouser designed for really cold, wet conditions. Now more waterproof and breathable, it also stretches with the lower body to allow an unrestricted running movement. Improved strength and a softer inner feel delivers warmth and comfort for relaxed training runs or long races.
Inov8's AT/C Racepant Waterproof U are a lightweight pant which are much more durable than the Ultrapant series. If you are going to be wearing these pants more often or smashing your way through the heather in races the AT/C Racepant will stand up to those challenges. With high levels of waterproofing and breathability these pants are a great option on race day or simply training days on the fells and mountains.
The stretchy fabric is really comfortable to wear in any conditions for as long as you need and does not restrict movement when in full stride like some other pants. The pants also have knee high zips making then much easier to get on or take of in a hurry. The pants pack down into a small pocket when not in use saving vital space for other necessities.