Chest size is 26- 44 inch, only for adults . Size Adjustable Sport Vest USB Rechargeable Led Running Jogging Light - Gift for Women Men Data Of Led Running Light Vest : 1, Bulb Type: 3W COB + RGB SMD 2, Power Source: 1200mAh Li-ion Battery( Included) 3,Backpack Size: 5.3in x 3.9in x 0.78in / 13.5cm x 10cm x 2cm 4, Product Weight: 6.3oz/180g 5, Material: PC 6, Operation Modes: Front Light: High light(160 Lumens) ¡§C Low light(100 Lumens) -Off Back Light : Slow multi-color rotation¡§Clock onto one color(Green, Blue, Red, Purple, Pink and Orange) ¡§C fast multi-color rotation 7, LED life: 100,000 hours 8, Working time: 8Hours 9, Features: Elastic reflective chest band with plastic buttons for adjustable use Red strings can glow in dark for safety warning Front strong white led bulb can use as flashlight ,work light etc Selectable multi color flashing modes inspired by visual science Light weight, super comfortable in running.