Conductivity

 is a Tier 5 Tank that upgrades from Glass Smasher and Iron at level 60.

Design
The is simply a combination of Iron and Glass Smasher. It looks very similar to Glass Smasher, retaining its hollow body, but its shell changes color to match Iron's unique shell.

Technical
The retains Glass Smasher's knockback immunity, with the added perk of debuff immunity.

Trivia

 * This and the Ulu Knife are the only two tanks to be both debuff-immune and knockback-immune.