K2 Phase Pro Helmet The 2018 K2 Phase Pro helmet is a great choice for skiers and riders looking for the ultimate in fit, comfort, convenience, and safety. You need to have some customization available because the helmet is, at its core, a hard plastic shell. K2 utilizes its K2Dialed fit system, which consists of a three-point contact system controlled by a simple dial that tightens or loosens the interior of the helmet. K2's Active Matrix Venting system allows you to control the vents with minimal effort, keeping you warmer or cooler. K2 Level 3 Baseline Audio - K2's Level 3 Baseline Audio system has an input jack in the back of the helmet and audio ear pads pre-installed. You can use the audio system of your choice and rock out to your tunes all day long. 490 grams at size medium