The JOYRIDE 4L is a lightweight performance kids backpack for bike, with outstanding carrying comfort and the same functional features as the adult models.Key Features:AIR TUNE SYSTEM offers perfect back ventilation,Compatible with optional hydration systems up to 2L,Hip belt (detachable),Material: N 210D RIPSTOP HD, 3D AIR MESH,Size: 4L, 300g, 39 x 20 x 6 cm.