A rotating datacenter proxy hands you a new server address as often as you ask, with datacenter exits instead of homes. On IPv4 you generate a list where every line is its own address: send each request through the next line and every request leaves from a different server, or keep one line to stay on its address. On IPv6 you send every request to one host and port, and the gateway picks a different address each time. It is the fastest rotating exit and the cheapest per gigabyte; it is also the one that tough targets recognize as a server range, which is what the residential pools are for.