Hard Leather Himantes

Pugilist's Arm, item level 14. Equip level 14, PGL MNK.

From 64 Storms on the Horizon and 1 more quest.

From quests

64 Storms on the HorizonChoose one of 4
72 The Spirit Is WillingReward

Other databases

Eorzea Database (the official one, on The Lodestone)
Console Games Wiki
Garland Tools (vendors, crafting, drops)