From Amazon
Nike Unisex – Adult's Slim waistpack 3.0 Bum Bag, Volt/Black/Silver, Standard Size
The product is available from £14.52 at international stores.
Running Point
Nike Slim Waistpack 3.0 Belt - Neon Yellow, Black - neon_yellow - nosize
RunningXpert
Nike Slim Waist Pack 3.0 Black Onesize