The Castelli Undersaddle Mini is part of the Castelli Race bags range and is the perfect bag for sticking on your road bike to carry some summer essentials.Super compact this fit and forget under saddle, seat-pack can be crammed with a couple of (road) inner tubes 18-25mm a multi-tool, a spare link. In short most of the things you might require on a ride. It fits with a single strap (through the rails no need for a seat post stabiliser), this strap uses magic moulded hook and loop fastener that can be trimmed at home and that won't fur your shorts. The Mini bag is also weather-resistant as is the zip. It's not totally waterproof but it's better than most. The zip pull sits in a little cave so it stays silent and doesn't open mid-ride. The rear wordmark is reflective and the lining is in a pimp corporate red.Features:Water and stain-resistant materialsWater-resistant zipperWater-resistant constructionAdjustable hook and loop attachment strapInternal storage pocketReflective accentsExternal dimensions 5 x 5 x 13cm (enough room for a Silca Italian Army Knife Tredici Bike Multi-Tool or similar 2 road bike inner tubes a spare link and some folding cash)