How excactly do mx O-rings work?

[ohm-ish]

I'm getting my first mechanical keyboard soon.
I got a very good deal on a Cooler Master masterkeys S (pbt, brown switches).
And I've ordered O-rings too, as I want a quieter sound and softer, less deep press.

When pressing down a keycap with an O-ring on, how does it hit the bottom excactly?

To me it looks like it would hit two edges of the MX casing top. Not the sides. Well maybe just a little bit.
(as the O-ring is circular and the MX casing hole is rectangular but wider).
Maybe this doesn't matter at all?

[suicidal_orange]

Yes the o-ring hits the top of the switch which prevents the bottom of the stem (coloured bit of the switch) hitting the bottom of the switch casing so there's no hard jolt when you bottom out.  A standard thin o-ring may well only hit the front and back of the casing but as you have to press straight down it doesn't really matter - they work

[JianYang]

If you get the cheap clear orings on aliexpress, the oring actually wedges in between the stem and the opening in the top casing, which makes for a very abrupt stop. Very hard to explain, but I find it surprisingly pleasant. To me it makes a brown feel tactile...

[ohm-ish]

Ok thanks

I ordered these.
Hardness: shore 50A.
Material: EPDM (that's the best right?).
Thickness: unknown. I hope they are not too thick (tall).
The shop has just these, in various colors and hardness. Pretty basic stuff I guess.