The parts of the Bunsen burner include the barrel, the collar, the air hole, the gas hose and a metal base. The barrel is a long tube that raises the flame to a more comfortable working height. It makes it easier to see the hottest part of the flame, which is blue, and the cooler part, which is bright yellow. Adjusting the gas and/or air flow changes the temperature and configuration of the flame.
The air hole, at the bottom of the barrel, allows air flow into the burner. A collar, also at the bottom, may be turned to adjust that air flow. The collar blocks the entire hole, or just a portion of it, to achieve that adjustment.
Below the collar is the gas intake valve. A gas hose, usually a rubber tube, attaches here and delivers gas from the gas source. In laboratory settings this is some sort of tap with a valve that regulates or closes off the gas flow. A built-in safety feature in the tap requires that the tab must be pushed down before it may be turned and opened.
The metal base is designed to be wide and heavy to keep the burner from falling over. It is common practice to put the base on a heatproof mat to protect the laboratory counter.