Pack yak

Pack yaks are level 96 Summoning familiars with the largest inventory among all the Beasts of burden. They have the capability of temporarily holding up to 30 items for a player. Pack yaks also have a special move called Winter Storage, allowing instant banking.

Pack yak pouch
A Pack yak pouch is made by using a Summoning on a Summoning obelisk with 211 spirit shards, a Crimson charm and a yak hide in the inventory. Making the pouch earns 422.4 experience points. Using the pouch to summon a Pack yak gains 48,000 experience points, and costs 10,000,000 Summoning points.

Winter storage scroll
Winter storage scroll enables the use of the Winter Storage special move for a Pack yak. Using the pouch on a Summoning obelisk creates 10 scrolls.

Winter Storage
Winter Storage is the special move for the pack yak, which enables an item in players' inventory to be banked, without the need of going to the bank in person.