I didn't use this much because I bought it just before my child outgrew head guards. ✴︎Product Description The shoulder strap belts can be freely adjusted to match the baby's growth. The straps are covered with soft cloth, reducing the load on the baby. The durability of the straps has also been improved, making them less likely to break. Generally, it can be used from around 6 months old, when the baby starts to sit up, until around 2 years old, when walking becomes stable. It comes with a strap to prevent slipping, making the backpack more secure and safe. 31.5cm x 20.5cm, thickness 4.5cm or more (head part) Babies who have just started to stand and walk really need constant supervision. Even if you are watching them, they often bump their heads when they fall. In case the baby hits their head hard, it can be serious, so how about a baby head guard as insurance? With a thickness of 4.5cm or more filled with padding, it absorbs impact effectively. It will be shipped slightly compressed. Please purchase with the understanding that this is a used item and has been stored at home.