The helix sense 450 is quite possibly the brightest and most feature packed rear light ever made. The unique sense mode includes a braking light which increases brightness when slowing down brightness sensing which automatically switches between daytime flashing and night mode and parking mode which automatically turns the light to standby mode when no motion is detected. In addition the helix sense 450 also has a group ride mode to allow you to be seen on group rides without dazzling your riding friends. Specification cob red led max. Lumens 450lm fl 1 tested max.runtime100 hrs fl 1 tested battery type li po built in recharge time 230 hrs size w x d x h 22 x 19.5 x 81 mm weight 40g features 5 modes day flash steady flash flash 1 mode 1 mode 2 cnc aluminum heat sink casing sense mode brightness function motion sensing function braking function parking function lock mode auto safe mode day flash mode mode memory function variable lumen system low battery charging and fully charged indicator automatic fully charged cut off system side visibility water resistance ipx7 rechargeable lithium polymer battery usb type c charging cable