These heavy duty, semi-rigid Blackmore 512 cell plug trays allow you to easily separate species in one tray, reducing potential disease spread, and easing transplanting. The plug trays measure 11"x 21 1/4" and easily fit into our 1020 no drainage trays, web trays, and Perma-Nest trays (lip of plug trays rest on top of other trays so that cells are in the trays. Depending on cell size, the bottom of the cells may not touch bottom of tray.) Use along with our heat mats and light stands for seed starting success. Cell size measures 7/8" deep and 9/16" wide. Plug trays are BPA free and made of recyclable #6 polystyrene.