The Yak-hide armour top is a piece of member's only armour. Initially after release, there were no requirements to wield the yak-hide top. Currently, a minimum Defence level of 20 is required to wear the armour. Yak-hide armour can be obtained either by using the Crafting skill or from trading with another player.
To make the yak-hide top the player must first have started The Fremennik Isles quest. The player needs 2 cured yak-hides (obtained from killing yaks and then tanned by Thakkrad Sigmundson), a needle and some thread. Creating a yak-hide top requires level 46 Crafting and grants the player 32 experience.
Despite the fact that the stats for this armour are not particularly high (midway between iron and steel armour tiers), it seems to provide better defence against the trolls of Neitiznot and Jatizso than armour with much higher stats does.