"Sliding Tray With Holes On Both Sides Of This Sofa"
Answer: "Tray table. It has another piece to it. It’s a tray with matching pegs. Tray goes on top and the pegs slide in. They fit together so the tray sits tightly. Then you take the tray back to the kitchen and put the sliding part back so it’s not in the way."
Pretty sure you are wrong.... the black/blue pages in those are thin. photo looks more like an album.
Better... er... what? That would depend on the specific function of the slide rule. I used these in an engineering drawing office early 70's
#56... That is what is left after removing a metal screen that was painted at one time
came with firearm accesories... Probably a wick for old gun.
But the two things can look more or less identical.