PMMA or Poly(methyl methacrylate) or more commonly know as acrylic or plexiglass 3D printing filament.

PMMA is commonly used as a replacement for glass and is very clear in it's natural form. This material also has the ability to be acetone smoothed to give a truly clear print! 

Recommended Print settings:

Extruder: 230-250C

Bed: 100-120C