A proselyte tasset is a Plateskirt that can be bought from Sir Tiffy Cashien in Falador after completing The Slug Menace quest. The quest is a requirement for wearing the tasset, along with 30 Defence and 20 Prayer.
It has equivalent offensive and defensive bonuses as a mithril plateskirt, while also offering a +5 Prayer bonus. It is white with a dark-gold trim.
This piece of armour is also part of the Proselyte Harness (f).
This piece of armour cannot be made using the Smithing skill. Even though this armour is trimmed, it cannot be obtained from any treasure trail.
The tasset, if part of a full set of the armour, can be stored in the armour case of a player-owned house.