ID holder "Mesh" opinions needed

[Firewalker]

Hello all, I hope each of you are doing fine.  I have a client who has put in an order to do a custom card holder similar to what her husband carries now with the addition of some tooling.  In the existing card holder there is an ID window and he uses it.   It doesn't have a plastic window but rather a mesh of some sort.  Has anyone used mesh to make it somewhat transparent and if so do you have any recommendations for what to buy?  

To date I haven't done the clear windows for ID and that may be because they don't seem necessary to me but it was requested so here we are.  I am sure I could just start trying different ones but if any of you have already invented the wheel I would appreciate any advice you might offer.  

Thanks in advance.  

Scott