The Ultra ATA/ 66 and Ultra ATA/100 Cable, is a 40-pin, 80-conductor cable. This Cable reduces crosstalk and improves signal integrity by providing 40 additional ground lines between the 40-pin IDE signal and the ground lines. This cable is backwards compatible, it works with Ultra ATA/100, Ultra ATA/66, Ultra ATA/33 and DMA, and with EIDE/IDE hard drives & CD-ROM drives