What is this device called?

A catalytic converter is an exhaust emission control device fitted into a motor, it converts toxic gases like CO, NO and HC to less toxic pollutants by catalysing a REDOX reaction.

A 2 stroke engine is an internal combustion engine which completes a power cycle with two strokes of piston during one crankshaft revolution. The 2 stroke engine emits more toxic substances from it exhaust. Most countries now permit the use of 4 stroke engines and ban the use of the 2 stroke engines.

A carburettor is where the fuel and air are combined and drawn into the engine for combustion.
A tail pipe is a device that exhausts gases from an internal combustion engine.