Boulder Jacket BLACK CHARGE MARIN ZEST The Boulder Jacket is a technical fleece jacket using pile fleece and is an ideal winter mid layer. The Boulder Jacket builds on the success of the Boulder Pull-on and uses the same Polartec Thermal Pro fleece fabric combined with panels of Polartec Power Stretch for extra freedom of movement. The Thermal Pro fleece is a deep pile fleece that is air permeable and is susceptible to air flow in windy conditions. This means that the fabric is very breathable