Velcro Strap-on seat packs.

Taillight hanger, 1680D nylon, Reflective strip & trim, Fits most seats.

Extra small: L: 11.5 cm (4.5"), W: 7 cm (2.8"), D: 6 cm (2.4")
Capacity: 0.4 L (24.4 ci). Weight: 52 g 

Carry limit: 1 kg.

Small: L: 14.5 cm (5.7"), W: 8 cm (3.1"), D: 6.5 cm (2.6")
Capacity: 0.6 L (36.6 ci). Weight: 61 g

Carry limit: 1 kg.