"Read Only" option not available in Shared Data?

"Read Only" option not available in Shared Data?


Hello,
I´m trying to set some permissions for shared data, for example products, so vendors can see products but not edit them or eliminate them. The option of "Read Only" doesn´t seem to show up, I don´t want my vendors to modify products or eliminate them.
The picture is in spanish but you get the idea.

Any hints of why is not showing up?