The 4I90 is an adapter that allows use of 4 MINI-PCI-Express cards (such as wireless network cards) on a PC/104-Express host CPU. The 4I90 uses a PCIE bridge so that the 4I90 only occupies a single, one lane, PC/104-Express slot. An optional one lane  cabled PCIE port allows attachment of remote downstream PCIE devices. The 4I90 has a local 3.3V and 1.5V switching regulators for the MINI-PCI-Express cards.  Up to 10A of peak current is available from the local regulators. Local status LEDS are provided and a connector for external LEDS and bridge GPIO bits is available. A passthrough PC/104-PCI connector is available for stacking purposes. Note that the 4I90 has two MINI-PCI-Express cards on the front and two MINI-PCI-Express on the back and may not fit with all CPU cards when stacked on top of the CPU.