The spacers are made of polypropylene, and this is the best type of plastic for medical and food uses because it is safe for human health and the environment. It is light in weight and can be used more than once. It absorbs shocks and is easy to sterilize. It is not affected by water, acids or solvents.and its sizes are different, including 1m * 1m, and there are 1m * 1.20m, and thicknesses of 2, 3, 4, 5, 6, 8, and 10 mm. Any sizes are available according to the customer's request.