Close The Loop – Join in and help Mammut make mountaineering more sustainable with a T-shirt we’ve made entirely from reprocessed waste. The Close The Loop functional T-shirt is 100% ECONYL® regenerated nylon. Some of the material comes from old climbing ropes collected by Mammut at select climbing gyms and stores. The Close The Loop T-shirt is lightweight, functional and perfect for outdoor activities all year round. It dries in no time and has a 3D material structure that makes it extra comfortable on your skin. Offset seams prevent uncomfortable pressure when carrying a backpack. To reduce unpleasant odors, the T-shirt is treated with HeiQ Pure technology developed in Switzerland. This helps conserve resources since less washing is required. And because it’s made of 100% regenerated nylon, the material can be reused over and over again – closing the loop. The T-shirt was developed by Mammut in collaboration with the non-profit organization Protect Our Winters Switzerland.