The CH31723 is a turbine engine igniter also known as a spark plug manufactured by Champion Aerospace. It is used to ignite the fuel-air mixture in the combustion chamber of a turbine engine, initiating the combustion process and generating thrust.
 
Here are some key features of the CH31723 igniter:
Part number: CH31723
Application: Turbine engines (aircraft,     industrial)
Material: High-temperature resistant materials
Design: Features a self-centering conical contact to minimize arcing and flashover
Interchangeable with: 369162, CH31824, and 3888210-1
Dimensions: 6.25 x 4.13 x 1.25 inches
National Stock Number (NSN): 2920-00-776-4482