... Twin Stack 4.5gal,horizontal Portable type Ingersoll Rand Ingersoll-Rand Portable Air Compressor P1IU-A9, Twin Stack, 2HP, 4.5 Gal Ingersoll Rand Portable Air CompressorLightweight, compact design makes ... --TANK ORIENTATIONHorizontalBase Model Number634158CFM @ 100 PSI4.3 Ingersoll-Rand Portable Air Compressor P1IU-A9, Twin StaIngersoll-Rand Portable Air Compressor P1IU-A9, Twin Stack, 2HP, 4.5 ...