Sigon's Wrap has the lowest level requirement out of all belts that provide 16 potion slots. It does have a fairly hefty Strength requirement at those levels, though.
Defense: 8-11 (varies)
Defense: (10-206) - (13-209) (varies)
Required Level: 6
Required Strength: 60
Fire Resist +20%
+ (2 Per Character Level) 2-198 To Defense (Based On Character Level)(2 Items)