From Ciele:

"RM stands for run mountains, in this case we're encouraging you to run in nature in a shirt made of natural fibres.

we mixed naturally hydrophobic wicking hemp fibres with an organic cotton to create this engineered Sorino material. a structured fabric with a soft hand-feel that is cool to the touch and delivers surprising performance to our NTRTshirt. the ample fit is airy while the loose cut allows for freedom of movement off road runs far from home. our first natural fibre performance T.

less plastic. more fantastic. nature for the win."