This molecular model set includes 135 pieces to allow students to build a large number of organic molecules. This is a great fit to any biochemistry class. Made of high durable plastic. Comes with case that has 4 divided sections molded inside to organize pieces. This molecular model set includes 135 pieces to allow students to build a large number of organic molecules. This is a great fit to any biochemistry class. Made of high durable plastic. Comes with case that has 4 divided sections molded inside to organize pieces.