Metal Coat

A very rare single-use consumable that makes your weapon permanently unbreakable for the rest of the adventure. If you've found a strong weapon early and want to keep it intact through the whole run, this is the item to use. Important exceptions: it does NOT protect the Nuclear Gun (which has a 20% break chance per shot) but DOES protect the Mini Nuke. Cannot gain additional uses from charge-restoring items. Use it on a weapon you're committed to for the long haul.

"Permanently unbreakable" means the weapon's durability will not decrease further — you essentially get unlimited uses of that weapon for the rest of the run. This has enormous implications for weapons with high damage but limited charges, effectively converting them from finite resources into permanent tools. The Nuclear Gun exception is notable: its break chance is a special mechanic not governed by standard durability, so Metal Coat cannot disable it.

Prioritize using it on weapons with high damage per hit and limited durability that you found early — the earlier you apply it, the more value you extract from unlimited charges. Feather Darts (99 uses) doesn't need it, but a powerful rare weapon with 5-10 uses becomes infinitely more valuable with this applied. One of the strongest run-extending items available if you have the right weapon.