Modular platforms are made of high density polyethylene plastic that is chemicaly resistant. They are easy to move and are durable. The top surface is grated and allows liquids and small particals to drain. All are 2 5/8" high. The Add A Mat is 1/2" thick and is made of an anti skid surface that reduces stress on feet, legs and backs. The plug lock system secures the mat to the level surface.