Timeworn Breastplate of the Mountains appears to be a well worn Breastplate. When the Goliath Fighter attune to the Breastplate, the wearer's Armor Class +1, and becomes immune to nonmagical cold damage. When the attuned reaches level 12, the Armor Class becomes +2, the attuned also has advantage on any saving throws on Death saves while in mountain terrain,  and speed is +10 feet while in mountain terrain.  When the attuned reaches level 17, Armor Class bonus +3, if the attuned falls off the mountain,  the wearer can cast Featherfall ( as the spell), and if the attuned falls to zero hit points, but not killed, the attuned can use as half movement to instead return to 1 hit point. 

This armor consists of a fitted metal chest piece worn with supple leather. Although it leaves the legs and arms relatively unprotected, this armor provides good protection for the wearer's vital organs while leaving the wearer relatively unencumbered.

Notes: Must be a Goliath Fighter