Here is a basic acrylic enclosure that can be used with both the A4 and A3 Emblasers.
We usually have these made from 4.5mm red tinted acrylic. At these specifications the laser absorption is equivalent to wearing the protective glasses supplied with the Emblaser.
We still highly recommend always wearing your protective eye-wear whenever you are using the Emblaser. You only have one set of eyes and safer is always better.
This design can easily be built by most plastics manufacturers.
Emclosure ( rev 0.1) drawings: Link