Keep yourself safe on the trails with the Schwinn Bunker ERT Bike Helmet. This Schwinn mountain bike helmet features Energy Reduction Technology (ERT) that uses a layer of waffle-shaped foam that flexes in multiple directions upon impact, redirecting force away from your skull. A streamlined design boasts 17 air vents to ensure you stay cool on warm rides, plus removable and washable moisture-wicking pads soak up sweat so it doesn't run into your eyes. A micro-adjustable dial retention at the back gives you the perfect fit with a simple twist. The Schwinn Bunker ERT Bike Helmet is finished with a removable visor to keep sun out of your eyes when out on the trails. The microshell construction provides lightweight durability. Medium fits 5359cm. Large fits 5963cm. ERT flexes to redirect force away from your skull on impact 17 air vents provide ample airflow so you stay cool Removable, washable moisture-wicking pads Dial retention system for the perfect fit Removable visor blocks the sun Durable, lightweight microshell