Power Conditioner

The 20PFI has a big toroidal transformer inside to help with blocking A/C noise.  It also has the Power Factor Technology "current reservoir".  This is a big capacitor inside the power conditioner which gives faster immediate current to your devices which the A/C line would not normally provide.  The 20PFI is very expensive, but these two items really provide a lot more.

The 15PFI also has the "current reservoir" capacitor, but lacks the toroidal transformer.  It's less expensive, but still better than the "DMI".

Yes of course you need both. And don't forget the Orange Fuse.

Hi millercarbon, 
Can you explain why do i need both with the Orange Fuse also? 

Because the fuse is almost as much improvement as the conditioner.

What about the utility to have both conditioner? 
Also, the swap of the fuses will void the warranty on the equipment?