Demonstrate all 3 classes of levers, plus fixed, moveable and block/tackle pulley systems. Build 8 different real-world models, one at a time with this 178-piece set. Includes activity cards for each model with real-life photo and key facts. Supports 3 students working in a team. Comes in a sturdy storage tray with moveable dividers and transparent snap-on lide. Grades 3-5.