Topeak Aero wedge saddlebag small in IGlow version with light (see picture 2).

Bag for mounting on a seatpost

Mounted with straps up under the saddle, and around the seat post

Rear-facing 3M reflector

With strap that provides space for rear light

The bag can hold 0.8 liters

Battery life approx. 50 hours at constant light and 100 hours at flashing.