Refurbished 5.5 Gen A1136 Wolfson DAC Model 

New LCD screen.

New Case and Clickwheel. 

New 3000mah battery instead of the stock 480mah.

Replaced stock 30GB HDD with 256GB Samsung Pro Endurance MicroSD card. Using iFlash QUAD, so there is room for 3 more SD cards for more storage down the line. 

Only quirk is that the "hold" button doesn't work, meaning you can't lock the clickwheel. I use my ipods in a dock or in a car so I haven't bothered to fix it, but it's a cheap and easy fix. Comes with car charger and sync cable.