"The Shovel Pocket can be one of the most useful compartments on a backpack. The ability to load oversize objects securely (like snowboards or showshoes) or carry things outside the packbag (they're great for drying tent flys in the morning on the trail) is indispensable on the trail. While most Dana Design packs have a built in shovel pocket (the BeaverTail Shovit), some of the most popular dana packs (Astralplane, Terraplane, Glacier and Bridger just to name a few) do not have the BeaverTail Shovit. Dana does, however, make a modular BeaverTail Shovit that can attach to any Dana pack that does not already have one.
I have one for my AstralPlane. This thing is rugged. It is made mostly of Hypalon and will not tear, and takes abrasion well. This serves as a great place to lash your crampons, if you aren't comfortable lashing them to the pack lid right behind your head.
The only problem is installing the thing. The directions from Dana are not that clear. My advice: separate the buckle straps that come with the Shovit and attach them to the Shovit, then attach them to the pack.
Once properly attached, the thing is snug and secure and does not interfere with any of the packs functions, except the Ice Axe loops. This is not a great loss, since the slots in the Shovit panels make a better place to lash you Ice Axe anyway.
The only other problem you may encounter is that unlike a built in Shovit, the modular unit does not directly attach at the bottom, so small items can fall out the bottom of the Shovit pocket.
But don't get me wrong. These problems don't really effect how well the unit works and it really is a very useful accessory. If you need to carry large items, or have problems with getting your tentfly dry, this is the item for you."