ROCKBROS bike bag is made of the most durable shell. The outside layer is PU+Polyester, the middle layer is 5mm foam, the inner layer is polyester cloth. Bike frame bag has 3 straps for install on bike tube. This 3 staps are sewing on the bag and can hold bag stable. The triangle bag won't move around even if you are riding on rough roads, and it is very easy to install by straps. The pouch fits most mountain, road and commute bikes.
