The Britool 1/2in Drive 14 piece metric impact socket set is supplied in a case with metal clasps which also converts into a modular storage system for use in roller cabinets:

14 x 1/2in Deep Impact Sockets: 10, 11, 12, 13, 14, 16, 17, 19, 21, 22, 24, 27, 30 & 32mm.
2 x Snap Rings.
2 x Safety Pins.