The BlackYak Calvana Collection brings together all of our expertise in user comfort and product performance. The advanced textiles in Yak Flow™ are tuned to allow a precise amount of air permeability. This continuous AirFlow™ prevents overheating and allows the fast removal of humidity and sweat build up. The result is a product that works as a midlayer during high output activities in cold weather and as a layering piece that optimises the vapour rate when used in conjunction with a shell product.