RuneScape Classic Wiki
RuneScape Classic Wiki
The main RuneScape Wiki has an article on: Rune Plate Mail Body
The Old School RuneScape Wiki also has an article on Rune Plate Mail Body.

The Rune Plate Mail Body is the strongest plate mail body available in RuneScape Classic.

A player must first complete the Dragon Slayer quest to be able to equip and buy a rune plate mail body from Oziach in Edgeville. In addition, a player must also have a defense level of at least 40 to equip it.

Besides Oziach, the only other way to obtain a rune plate mail body is through the smithing skill. Players can smith rune plate mail bodies from 5 runite bars at level 99 smithing, giving 375 experience.

As with all plate mail bodies, wearing this means you are unable to equip any gloves, which, to some players is a disadvantage as Klank's Gauntlets and Steel gauntlets provide a WeaponAim and WeaponPower bonus. Some players choose to wear a rune chain mail body and gauntlets over the rune plate mail body, which in theory should kill monsters faster and raise XP and drop rates.