The Icebreaker Oasis Longsleeve Womens Crewe Thermal Top 2020 is exactly what you need in a base layer. Available in lightweight 200gm fabric, the Oasis thermal top will keep you warm when you're hitting the descent, and made from 100% merino wool, it will effectively and efficiently wick moisture off your skin. Made in a comfortable slim fit, this thermal is a no brainer - no wonder it's back in store again.