An ultra-versatile helmet that is light, cool and sleek with the added protection of WaveCel helmet technology. If you get just one helmet, make it this one Whether your finish line is on the race course or your front door, Trek Circuit WaveCel delivers the performance, comfort and tech to be your go-to helmet. It's equipped with features that any rider will appreciate, like WaveCel technology, a BOA® Fit System and Blendr mount systems.  WaveCel is a collapsible cellular structure that lines the inside of the helmet. This Trek-exclusive technology disrupts the safety standards that the industry has accepted for over 30 years. Product details WaveCel advanced helmet technology The BOA® Fit System lets you easily secure and adjust your fit with one hand The Blendr magnetic mount system easily integrates a GoPro camera and Bontrager lights Made of 50% post-consumer recycled polystyrene FlatStrap semi-fixed strap dividers lay flush and move fore and aft for a perfect fit Soft, comfortable, moisture-wicking and washable helmet pads Reflective elements on the back of the helmet offer enhanced visibility The Crash Replacement Guarantee provides free replacement if your helmet is impacted in the first year of ownership Size S M L XL Circumference 51-57 cm 54-60 cm 58-63 cm 60-66 cm Fit system BOA® BOA® BOA® BOA® Pad material Moisture wicking pads Moisture wicking pads Moisture wicking pads Moisture wicking pads Buckle type Standard buckle Standard buckle Standard buckle Standard buckle Includes Crash Replacement Guarantee Crash Replacement Guarantee Crash Replacement Guarantee Crash Replacement Guarantee Weight 320g 345g 385g 400g