what visual difference is between this types of hotsides. I have one hotside, want to know which one it is. thanks

it has one flapper. i think one flepper hotsides are only 10.5. is not it?

It will be etched into the hotside

??? cant anderstend

If it is a single flapper then it is almost sure to be a 10.5cm housing. I have a 9.0 on the shelf and it is a dual-flapper configuration. Most all 9.8cm housings were dual-flappers. I had one of those.

However, I did read about an optional 9.8cm single flapper, but I have never actually seen one. Apparently it had to be special ordered. So, I am not so sure that they did in fact exist. It would be extremely rare. So, I am 99.5% sure that it is a 10.5.