Pumping out an attention grabbing 300 lumens with opticubetrade lens technology the versatile viz300 stands out with the power of daytime hyperflashtrade mode and the friendliness of group ride mode. Dimension 25 x 75.5 x 34 mmweight 47g with batterieslight source65306red led x3battery65306li ion rechargeable batteryruntime65306constant 30 lumens653065hrsflashing 30 lumens6530645hrsgroup ride 15 lumens6530610hrsdaytime hyperflash 300 lumens6530610hrsrecharge time653063hrs 0.5amount size65306phi21.5 32mm. Fits up to 130mm outer circumference. Sp 15water resistant ipx4other battery auto save low battery indicator light mode memory 3 leds 300 lm highly visible during daytime 300 degree visibility long rear beam projection opticubetrade lens technology lithium ion rechargeable battery usb c rechargeable usb c cable not included low battery indicator four light modes constant flashing group ride daytime hyperflash mode memory function battery auto save the mode automatically changes to flashing when the battery power gets low. New seat post bracket sp 15 which fits contemporary kammtail aero seatpost snap systemtrade