At least I think that’s what it says in the red writing at the bottom of the fuse box or maybe it says don’t remove this fuse. These are Buss 30W fuses. I think Buss fuses are still made although not in this form…probably. The bottom of them resembled the bottom of light bulbs as you screwed them in and out of the fuse box. Whatever it was they once made in this factory seemed to require at least a couple of these fuse boxes on the ground floor or maybe that’s all that survived.
This is what they looked like when new: