DIY HELP – the rubber strip between window and frame

What’s it called?

Replacing some rotten wooden beading outside of a window pane. Google skills have failed me. What’s the rubber strip that would sit between wooden bead and the glass called?

I assume it’s there to provide some weather proofing as well as cope with wood expanding/contracting with the weather.

Tried lots of searches but nothing appearing looks like what I need.

Could be a wedge bead

Only showing wooden beads.
That search led me to window gaskets but they all seem a particular contour. I think I just need a plain flat strip/roll of rubber or whatever material it’s made of.

Flexistrip? Basically mastic on a roll used to glaze wooden frames, modern alternative to putty. Must be 20 years since I used it, but still got a box in the garage…

Whichever seal it is, I’d expect these guys to list it.

https://www.reddiseals.com/

Flexistrip that looks like the stuff, thank you steveb ?

Clear glazing silicone. Soudal, Dow 799, etc.

Get hardwood glazing bead, well worth the extra ££

Glazings normally on foam tape…

My timber sunroom is. Against the glass and beads I’ve trimmed shitty silicone etc out taped and used ob1 clear.