I got the 12x8.5 inch one here, you can find the same one searching "acrylic riser" on amazon.ca if you're in Canada :) https://www.amazon.com/gp/aw/d/B074CB3P4V/ref=mp_s_a_1_5?ie=UTF8&qid=1523233740&sr=8-5&pi=AC_SX236_SY340_FMwebp_QL65&keywords=acrylic+riser