https://www.wowhead.com/item=90087 is a One-Hand Fist Weapon dropped by https://www.wowhead.com/npc=66936, an NPC which you can summon with the https://www.wowhead.com/item=90172 in Krasarang Wilds.

How to get the Clamshell Band

To make the https://www.wowhead.com/item=90172 you will have to loot clamshells from six other makrura-type NPCs scattered throughout Pandaria.

/way The Jade Forest 59.8 95.8 Akkalar
/way The Jade Forest 59.2 36.6 Akkalou
/way Dread Wastes 27 69 Clamstok
/way Krasarang Wilds 39.4 88.6 Damlak
/way Kun-Lai Summit 42.4 24 Kishak
/way Kun-Lai Summit 54.2 21.6 Kishak
/way Townlong Steppes 42.6 92.6 Odd'nirok

Clawlord Kril'mandar

After obtaining all 6 items, you will be able to fuse them together to create the https://www.wowhead.com/item=90172. Then you can make your way over to Krasarang Wilds to summon https://www.wowhead.com/npc=66936.

/way Krasarang Wilds 12.6 82 Clawlord Kril'mandar

Upon defeat, the item https://www.wowhead.com/item=90087 will drop.

If you loot this item, bear in mind that there must always be... a Pinch King.