Easy to install and quickly attach with Velcro (Velcro).One size fits all, so you dont have to worry about choosing a size. Not only can it be used as a light holder when diving, but it can also be used in a variety of ways depending on your ideas.For example, it can be used for walking your dog at night, security, night fishing, mountain climbing, etc.No need to hold the light in your hand, but it is extremely convenient to use both hands freely.