GIVI V56NNTA Maxia 4 56 Liter Monokey Topcase Maxia 4 Matte Black Top Case with Silver Trim, Grey Lenses and Faux Carbon Fiber Top Pannel 56 liter capacity and can hold two full face helmets. Dimensions : height 12.9" x width 23.6" x depth 18.8" Requires Bike Specific or Universal Monokey Mounting plate to install (sold separately)