Here is a brand new old stock late model MFM hard drive controller, from market leader Western Digital. It supports 2 internal hard drives. This is a 16-bit ISA card.Earlier model hard drive controllers had a slower data transfer rate. This one makes a difference since it supports 1:1 interleave. Previous controllers had logic chips which weren't fast enough to keep up with a 3600 RPM hard disk, but this one can tell the heads where to go in the first revolution of the disk (instead of waiting for the 2nd, 3rd, or 4th time that location spins under the head).Buyer will receive the exact item pictured here. Documentation Included. .