Optionally provides up to 900mA per USB port. Provides two external USB 3.0 connections. Built-in optional SATA power connector for bus-powered USB devices.
Does exactly what it says on the tin.
As one would expect, a PCI-66 card cannot be as fast as a PCIe card, but this one does rather well: on old Core2Duo-based system, can get over 100MBytes/sec to a USB SSD.
Rather fantastic, considering.