Methylacetylene-propadiene (MPS) gas is a type of fuel gas used in oxy-fuel welding and cutting torches. The most commonly known type of MPS gas was MAPP gas.
This gas was a mixture of propyne, CH3C≡CH, and propadiene, CH2=C=CH2. As a fuel gas, it burned hotter than propylene, propane or natural gas. It also had better heat distribution than acetylene.
References
Methylacetylene-propadiene gas Wikipedia(Text) CC BY-SA