A 399-piece set designed for hands-on STEM and simple mechanism learning at home or in the classroom. Self-locking ABS bricks give you sturdy, reliable connections so models stay together while you experiment and learn. Parts are compatible with standard small building bricks, letting you mix and match with existing collections for more creative options. Easy to assemble and disassemble — ideal for DIY projects, model builds and exploring mechanical principles. Includes pieces compatible with model references like MOC EV3 9686 and 9689. Supplied as the 399-piece variant (no box).