The iFlash-Dual is a board designed by Tarkan that allows for 2 SD(HC/XC) cards to be used in place of the 1.8" ZIF Hard Drive used in the iPod Video (5th generation) and iPod Classic (6th and 7th generations).

Front side of the iFlash Dual
iFlash-Dual Compatibility
Can be inserted 2 full-sized SD cards
2 microSD cards with adapters
Compatibility (iPod video & iPod classic) Yes.png Fully natively compatible
Yesblue.png 6th generation "160 GB thick" iPods REQUIRE an HDD ribbon to be used with iFlash-Dual.
Compatibility (iPod (4th generation)) Yesblue.png Compatible, with 4th gen iPod to iFlash converter.
Compatibility (iPod (3rd generation)) Yesblue.png Compatible, with 4th gen iPod to iFlash converter.
Compatibility (iPod (2nd generation) and earlier) No.png Incompatible.
Compatibility (iPod mini) No.png Incompatible.

Resources

Link to iFlash's Website page about the iFlash Dual: https://www.iflash.xyz/store/iflash-dual/