Camshafts are used in internal combustion engines (to operate the intake and exhaust valves), mechanically controlled ignition systems and early electric motor speed controllers.
Charcoal briquette is a kind of fuel made by charcoal powder. Compared with traditional fuels, charcoal briquettes can not only generate heat continuously but also produce no smoke and odor during combustion. The product is safe to be used as the fuel for cooking and keeps the heat last longer than normal charcoal.