Yes, that's a bubble axis that you can slot into the hotshoe of your camera to show everyone that you have problems leveling your horizon. I have a bubble axis on my Benro tripod and every once in awhile I look at it and think: what is that? No, I never use it. I don't understand how someone can't tell their horizon is not level from looking through their viewfinder. Okay, some cameras have extremely crappy viewfinders; but those are on point and shoots and really you are unlikely to be using that for your spot on landscape. To be fair, I have shot my share of landscapes where the horizon is off -- well, like the comment in the link says: I just crop it.

I got back from a quick couple rounds through the Croatian Cultural Center camera show and came out relatively unscathed. I said I would only spend what was in my wallet and spent half of that to get:

-- Asahi Spotmatic with leatherette cover and 55mm Takumar f/1.8 lens. Body in about C+ condition (couldn't test light meter since it had no battery)* but otherwise seemed to work and the 55mm in great shape (B) -- $20

-- Bushnell / Bausch & Lomb 135mm f/2.8 in M42 mount in stellar condition (A-) for $5.

Update

*After researching more about the Spotmatic it seems that I and the dealer just didn't know how to make the light meter work.

I got a replacement ground glass in the mail yesterday from Steve Hopf, who is well-recommended in um ground glass making circles.

Initially there was a sizing issue with an early one he had sent and me lacking glass cutting tools I asked him for a replacement with correct measurements and he obliged. You can find him on that auction site or on Facebook. This new one fit just fine onto the back of my Pacemaker Speed Graphic and instantly there is a big difference between what I was seeing before and now (plus the old one is in a landfill after my accident).

Not quite so random. I had planned on going somewhere this Sunday to spend film wisely but time and later the destruction of my ground glass in that tripod collapse made sure I stayed in my backyard. This test picture of the um plant in my garden I took just so I could try and get a detail shot. I think it shows that the lens at least is just fine (and also my focal plane shutter is pretty fine as well shooting 1/30th).

Forget to tighten one of your tripod legs and find out.

I didn't exactly count all of the shards since parts of the ground glass were basically pulverized on impact with my floor. I was mostly screaming and cursing. I even threw my cowboy hat onto the ground. How is that for an image? I may even have shouted: "jumping jehosafat!" By criminy!

My fault: did not tighten sticks

Anyway, I had my mind on some other things and set my Speed Graphic on my Benro sticks and didn't check to see that everything was tight. Just the other weekend my buddy with his Gitzo showed me how his sticks lock tight with a twist. The Benros don't. You have to tighten and tighten and it's either tight enough or it isn't -- no snap no lock. So after I put it on its feet as I was talking to Sarah one of the legs lost tension and it all slipped down and I watched in slow motion as the Pacemaker swung down.. BSHHHHHHhSHHH! went the glass.

After carefully taking a picture today when I rammed the dark slide back into the holder I pushed the negative back out the other side where it fluttered to the ground. Argh. Really, I was more afraid that someone saw me do that than I was mad about the lost negative.

Update
Apparently, my error was that I had inserted the negative into the dark slide slot rather than in the slot lower. It would have been unlikely that my shot would be in focus anyway.