RuneScape Classic Wiki
RuneScape Classic Wiki
The main RuneScape Wiki has an article on: Bronze Plated Skirt
The Old School RuneScape Wiki also has an article on Bronze Plated Skirt.

The Bronze Plated Skirt is a plated skirt that can be made using 3 bronze bars at level 16 smithing, yielding 37.5 smithing experience. It can be worn by all players.

It can be exchanged for Bronze Plate Mail Legs from Thrander in southeastern Varrock, and can be bought from Ranael's Plateskirt Shop located in southeastern Al Kharid.