OLFA's double-sided mats have a green base color with yellow grid lines clearly marked on one side for easy measurement identification, and solid green on the opposite side for general use. The mats are 1.5mm thick for exceptional durability. The 12" by 18" mat is intended for those small delicate cutting needs. Especially designed for use with OLFA rotary cutters. Always store your OLFA Rotary Mats flat.