Buy RS3 Yak-hide
Yak-hide is a members-only item in RuneScape 3. Yaks always drop it, and you can also get it from Spirit implings, Spirit yaks, and Fremennik yaks. Each hide weighs 0.453 kg and can be traded or noted.
Yak-hide has two main uses. First, it is a Crafting material. Take a hide to Thakkrad Sigmundson on Neitiznot and he will cure it for 5 coins. Cured hides can be made into yak-hide legs and yak-hide bodies with a needle and thread. Legs take 1 hide and bodies take 2, but both give 32 Crafting experience, so making legs is the better way to train.
Second, yak-hide is the tertiary ingredient for Pack yak pouches. Making one takes 211 shards, a yak-hide, a crimson charm, and a pouch at a summoning obelisk. This needs level 96 Summoning.
Yak-hide armour needs level 20 Defence to wear. It matches black armour in Defence but weighs much less. It also lowers the max hit of some Ice trolls, which makes it useful in The Fremennik Isles quest.