Thrander is a non-player character located in Varrock, south of the eastern bank in a small house containing some anvils. He provides a free service of converting armour designed for men into armour more comfortable for women (and vice-versa). Items can be converted by using them on Thrander, talking to him normally just provides an introduction to his services.
Thrander's presence had an effect on the game economy. Since items could be changed instantly at no cost to players, this ensured they retained equal value. Thrander was never present in RuneScape 2 and later versions, where skirts generally had lower values than plate mail legs. He briefly returned to Old School RuneScape during the 20th Anniversary and 25th Anniversary events.