Vlies abrasives : how to guess grit number ?

[cocodou]

In my sanding storage systainer, i have 2 types of Vlies abrasives : S800 (497404) and A280 (497403).
Problem : there is nothing printed on backside, and honestly it is very hard to guess which is softer than the other by touch.
The only distinctive sign is colour : one is grey, other is brown... but how to tell which is which ?

Does anybody know ?

 

[Les]

Check this link to Festool USA abrasives chart. Look at page 10 of chart for Vlies info.

 

[cocodou]

All right. I did read the chart but obviously not pay enough attention.
Thank you Les.