Boom Cylinder is the long metal tube that helps our machine lift and lower the boom. Inside, a piston moves when we send hydraulic oil in. We connect one end to the boom and the other to the frame, so it acts like a muscle. When we push oil in, it extends; when we let oil out, it retracts. We check seals and oil level to avoid leaks. It is strong but needs care. Without it, our boom would flop around like a wet noodle.