This is a high quality fully lined water resistant (not 100% waterproof) top tube frame bag. It has 3 velcro straps (2 with buckles) for secure but quick and easy fitting / removal.
It is thinner than many others on the market (5.5cm) so therefore better suited for bikes with thinner frames.
There is an easy access mesh pocket on the outside and a velcro pocket on one end of the bag.
Its dimensions are 18cm Wide x 12cm High x 5.5cm Deep so there is ample room for essentials such as keys, money, hand tools, puncture kit and most mobile phones