This set includes a friction block and a friction board, both made of high quality smoothly finished pine wood. The friction block has a hook for a spring scale and 3 compartments for additional weights. It can be placed face up or sideways. Students can vary the weight or area of contact to test their impact on the frictional force. The set comes with three 50g weights and a 100g spring scale. The board measures 20 x 2 inches and the block measures 4 x 1.5 x 1 inch. An activity guide/manual is included with the set.