Puff is a student-designed bi-propellant rocket engine that is designed to produce 2kN of thrust. It uses a mixture of N2O and isopropyl alcohol for its propellants. 

Unlike most engines entered into Race2Space, Puff utilises an ablative-heatsink method to regulate its thermals. This method involves placing an ablative, phenolic insert within the combustion chamber, with an external steel sleeve encasing the engine. It is this casing that gives Puff its unique appearance.

The engine mainly uses machined parts apart from the injector (shown at the top of the image), which, due to complexity in the design, was 3D printed out of 316L Steel.