1.1: Rear Box Size: Small size: 14.2 x 9.1 x 8.7 inches (36 x 23 x 22 cm). The large size can hold helmets and is suitable for big cars, while the small size can accommodate half helmets or shovel helmets, chargers, umbrellas, and is ideal for compact cars. Check which rear box fits your model. 2.2: The entire body is made of aluminum magnesium alloy, lightweight and impact resistant. hardness and toughness ensure long lasting durability. The internal structure is well organized with compartments, functioning like an integrated jewelry box. Features include a cosmetic mirror, removable design, and enhanced practicality. Available in matte and glossy finishes. 3.4: Trolley attachment strap allows easy placement on luggage, freeing both hands for effortless travel. Reinforced wrap corners and rivets provide all around impact resistance for durability. Can also be mounted on motorcycles and scooters using brackets. 4.3: Secure combination lock for easy, theft proof use, includes 2 keys for convenience. The ergonomic handle features automatic slow rebound for comfortable carrying. Grab and go anytime with ease.