The osprey duro solo belt the duro solo belt is built for the minimalist with both lightweight construction and maximum functionality it features an ergonomically shaped 570ml hydraulicstrade bottle designed for easy single handed access and secured by an elasticated retaining strap duro solo also has a tpu touchscreen smartphone window allowing you to control your tunes or check your training app while on the go the securely fastened pocket has a good amount of storage for gels s