Kobomite

Kobomite is a lightweight, but tough metal that is exceedingly rare and highly coveted throughout Colarn. The Dwarves of old would make masterful works of craft from weapons to armor out of what little they could find. Only small amounts are ever found while mining into the ground and it could be decades of mining an area before even a few pounds of the metal is ever found, Kobomite, besides being light and tough, also has an anti-magic property. This means that enchanted Kobomite doesn’t exist, but anyone wearing Kobomite armor can’t be harmed by direct magical attacks and anyone wielding a Kobomite weapon can easily penetrate magically enchanted armor or magical barriers. Spells used to weaken or destroy the armor or weapons themselves automatically fail and magic that would cause instant death or decay have no effect.
Though it is strong it is less durable than adamantine or mithril, but more durable than steel. Despite the lesser protection it would give in relation to the stronger material, Kobomite is still a well sought after metal. Many consider the anti-magical effects a fair trade off for less protection.
Unbeknownst to the wider world, extremely large deposits of Kobomite have been found in Askaria and have been studying it for its use in anti-magic weaponry and protection. What has been surprisingly promising has been experiments in turning Kobomite into a protective coating for vehicles.
Gray Rot Swamp is a cursed place and has long been known to have the ruins of a dead civilization in its waters. The foliage above makes airship travel too treacherous and anyone attempting to go in by water will see their boat swiftly start to age and decay out from under them and plunge them into the water where the unfortunate victims will also rapidly age and decay.
Kobomite has been proven to negate the effects of the swamp water, but making the entire hull of a vessel out of it would not be cost effective. The spray form allows one to simply spray the hull and gain much of the effect of metal Kobomite. It won’t give those in the vehicle total immunity to magic, but it gives it resistance to it and in the case of cursed swamp waters, the resistance is more than effective to negate the harmful effects.
The Askarian military is also looking into coating their vehicles with spray on Kobomite to give their air and sea going ships valuable additional protection, but it is still in the testing stages and wide spread production has not yet begun despite the urging from the military.