What is this?

[drjackool]

What is usage of these ring rubbers exist in Crystal 570 kit case?

 

[Calvin7]

Tempered glass uses 4 spacers each on side and on front.

 

[drjackool]

Tempered glass uses 4 spacers each on side and on front.

This is incorrect, bnecuase this case has 4 glasses on sides and i don ot see these rings on them.