What is the model of the Auxiliary Power Unit (APU) mentioned?

The Sundstrand APS 2300 is recognized for its application within various aircraft, serving as an Auxiliary Power Unit (APU) that provides electricity and pneumatic power. This model is specifically designed to support the operational needs of commercial and military aircraft by supplying power for starting engines, environmental control systems, and various onboard systems when the aircraft is on the ground or during flight.

The significance of this APU lies in its reliability, compact design, and efficiency, making it a popular choice for aircraft manufacturers. Additionally, its integration into aircraft systems helps improve operational flexibility and reduces dependency on ground power sources. This understanding of the Sundstrand APS 2300 highlights why it is the correct answer in the context of the question asked.