ID Card Holder

I designed and created this ID card holder, it can put two standard cards with dimension 86x54mm. The card are slot in thru the top opening, after which the clips will hook onto the slot hole. Thus preventing the cards from falling. Within the upper slot. I have also include a 1mm height stopper. Also strengthen this area.
This is a open card holder design, it is good for office card entry or transport transit card usage.
The overall thickness is just 5mm. The backing is just 1mm in thickness