1/8" Specialty Cast Acrylic
One side has a matte finish
One side has a glossy finish
Standard (12" x 19") sheets
Paper masking on both sides so it is laser-ready with no need to remove or replace unless desired.
The settings I start with on my Glowforge Pro are medium black (adjust settings as needed)
 
*The photo posted is made to most accurately reflect how the acrylic looks in person, the actual product coloration/patterns may vary.