Laser cutting quote material explanation

I received my first quote for the shredder parts and there are three different mild steel grades used. Could anyone comment on what these are and why they have been chosen for each area of the shredder please?
please see attached quote

Hi Duncan,

Looked at your quote,
3mmCR4 is a ColdRolled normal steel
S275 is a (Hot rolled) normal steel

304 is a Stainless steel grade, where the 2B stands for a finish, 1 side mostly protected by a (white) plastic foil.
The H/R stands for Hot Rolled, is used for St.steel thicker than 3 mm.

So you have two quotes in one.
a cheap one for rusting steel and a more expensive one (my choice) for a stainless steel version…

Price is similar to what we paid for in the Netherlands, so a good deal I guess…

Please be ware, you can change the sieve “24-48888-17 Sieve” to 3mm thick (my fault 🙁 )

Check This Post…
new files

Thank you, the quote makes a lot more sense now:-)
I concur that the sieve sides need only be 3mm not 6mm.
Could you just confirm that the information in the thread you steered me towards, about reducing the quantities slightly and the bearing spacer dimension, relating to the new shredder design and not the old one?
Thank you Duncan