This article uses content from the The Mary Poppins Bag article on the Warehouse 13 Wiki.
Artie's Bag
General Information
Source Unknown (presumably Mary Poppins)
Danger Minimal
Location In Artie's possession

Artie keeps a bag with him at all times, stocked with handy artifacts such as:

There are also several items used to neutralize artifacts or block artifact effects, such as specially designed earplugs, nasal spray, and a neutralizer aerosol spray. He also seems to keep at least one seemingly plain tennis ball in this, which he used to set off a chameleon mine in Time Will Tell. Also, he is seen to have a ping-pong paddle and a seemingly-ordinary brass compass in his bag when H.G. and Myka look through Artie's bag in Vendetta.

Whether the bag itself is an artifact, or at least possesses unusual features, is, at present, unknown, but certainly not beyond the realm of (Warehouse) possibility. Artie himself seems to view it much like a doctor's black bag, providing not only the materials required, but also functioning as a tangible reminder that he is trained for, and can handle, this, whatever "this" might happen to be this time. Pete has commented on th fact that it always seems to have exactly what Artie needs, but Artie shushed him before he could finish, saying not to jinx it.