ROCKBROS Bicycle Bag Portable Cycling Top Bottom Tube Bag MTB Road Phone Tool Bag Reflective Ultralight Bicycle Pannier Pocket

The reviewer discusses a top tube bag from ROCKBROS, noting it is commonly used by gravel cyclists but also suitable for road bikes. It allows carrying gels and energy bars, freeing up pockets. The bag has a low height design to avoid knee rub when out of the saddle, a water-resistant zip, and a rigid construction that doesn't bow out when filled. It can be attached with Velcro straps if the bike lacks top tube mounts. The reviewer finds it a good way to carry more food and considers it a very impressive little product for £8.