Except for very large examples, lubrication was almost always manual. Main crankshaft bearings and the connecting rod bearing on the crankshaft generally has a grease cup—a small container (cup) filled with grease and a screwed-on cover. When the cover is screwed down tighter, grease is forced out of the bottom of the cup and into the bearing. Some early engines have just a hole in the bearing casting cap where an operator squirts lubricating oil while the engine is running. The piston is lubricated by a drip oiler that continuously feeds drips of oil onto the piston. The excess oil from the piston runs out of the cylinder onto the engine and eventually onto the ground. The drip oiler can be adjusted to drip faster or slower depending on the need for lubrication, dictated by how hard the engine is working. The rest of the moving engine components were all lubricated by oil that the engine operator had to apply periodically while the engine was running.