OMM says: Durable compressor with water resistant pocket specially shaped to accommodate your choice of equipment from Skins, Avalanche probes to Crampons. Compression straps allow attachment of Skis, Snow shovel and even your deadman. Aluminium buckles are resistant aganist Ski edges. Multiple attachment points for even compression, built in Dyneema fabric for extra strength and durability.
OMMs Winter MSC Kit is a pocket with straps and hooks that allows it to be fitted onto the front of OMM rucksacks, as its designed to take crampons and other hardware its a tough pocket and the straps can be used to compress the load.
Its a really good idea! If you're venturing into the winter wilds having your crampons accessible is really useful.