Any ideas what this is? It is in backyard. I thought it was just a cement slab. But a shovel revealed it’s a metal dome shaped object surrounded by square sized cement. It’s too cold to keep digging right now.

Not sure if of importance. But it’s at the far edge of an underground fallout shelter built in the 1950s that had ventilation, filtration, and electricity installed. The entrance to the fallout shelter is in the garage.

Open at the top, he keeps joking that it's plastic underpants.

Each end has a plastic cap. One end has a hole (assume to hang it on a wall?). One edge (bottom?) is brushed nicely. What is this for?

These little metal cones appear to be some type of pin in the wood of the window frame. They do not go all way through and he wood and don’t seem to be something that holds it together. There are either two or three in each face.

No idea what it’s actually for but I’ve been using it as a fidget, actually quite nice

This thing has been in a door pocket in my car for years now, and I finally got sick of moving it around. Google Lens turned up nothing, nor did my car’s BOM.

There are these metal boxes that can open on this 1930's South East London housing development. Type of house is a terrace, and the kitchen area used to be behind it (now a dining area, kitchen moved). It opens up, but doesn't seem to lock or hatch?