Please leave an note at your check out page, M:54-58cm, L:58-62cm,  three colors available, all black, black/red,black/grey( remote controller include), thanks.

LIVALL MT1 Bike Helmet is not only a helmet. LIVALL Smart Helmet = Turn Signal + SOS Alert + Phone Calls + Music Player + Walkie-Talkie.

All for Safety: Safety is Top Priority. Hereby we present you LIVALL Smart Helmet, a multi- functional helmet which provides you more than safety.

Get Help in Time: Added a 3-axis G-sensor to the helmet to make sure you can get help in time in case you fall. Once the G-sensor senses unusual gravity acceleration, the emergency signals on the helmet will be turned on and an SOS alert will be sent to your emergency contacts automatically. Very useful when you’re cycling alone.

Product Parameters: Bluetooth: BLE4.0+HFP/HSP/A2DP Bluetooth Distance: Max. 10m (if no blocks) Speaker: Stereo 2x0.5W Mic: -39dB microphone Tail Lights: 8 full-color LED taillights with 3 left-turn/3 right-turn signal lights Buttons: Three buttons, turning on/off (play, pause), volume+- (previous/next song) Charging Ports: Micro USB Electrical Parameter: DC 5V/0.5A Battery Capacity: 3.7V/380mAh (1.4Wh) Charging Time: About 1.5 hrs Battery Endurance: Max. 10 hrs Standby Duration: Max. 180 days Product Size: 280x220x150mm Product Weight: 319g (±5%) Size: Head circumference: 54-58 cm , 58-62cm.  Color:  black and red, black and gray, and all black.  Warranty: one year

https://www.youtube.com/watch?v=pkaXfcHoICg&t=10s

Package Includes: 1 x LIVALL MT1 Smart Bike Helmet 1 x LIVALL Remote Control 1x USB charging cable 1x product instruction 1x warranty card CPSC and EN

After sales service :24/7 001-647-939-1600