Not quite the quality/functionality I would expect from Lezyne. Smallish, but that's to be expected given its top-tube mount. Holds a couple of energy bars and a few gel packs; maybe 800 calories. Clear cover is not very wide, only attaches at end, and provides no security along the length of the caddy. Velcro attachments to top tube and head tube are OK, but whole thing tends not to stay upright, preferring to tilt to the left or right. On a recent century ride I noticed similar top-tube bags from other manufacturers that appeared to have better closure and/or larger capacity.