stack
stack, The Stack's innovative design offers unrivaled space saving and modern styling, and has a double safety certificate in the US and EU. Weighing only 330 grams, The Stack features hidden air vents for extra breathability, a dependable locking mechanism when fully expanded, and an adjustable elastic strap.Reduces size by more than 40%Weighs only 330gComfort Adjustable Elastic StrapVentilated with Hidden Airflow OpeningsCSPC Certified in US & EN1078 Certified in the EUEstimated shipping date of December 18th, just in time for Christmas delivery!Medium (most common size) fits riders with head circumference of 56-59 cmLarge fits riders with head circumference of 60-63 cm