The Shell Shield is equippable at level 7 by Warriors, Red Mages, Paladins, Beastmasters, and Samurai. It provides a bonus of 2 to Defense, 1 to Vitality, and 2 to Water elemental defense, but has a -2 penalty to Agility. It can be obtained by battling Young Quadav in the areas near Bastok. The Shell Shield can also be used in the quest "Welcome to Bastok", or to upgrade an adventuring fellow's shield.
Shell Shield is a high-ranked shield, found in the Stilshrine of Miriam or as a reward for the Wyvern Lord Hunt. It provides 5 Evasion and the Auto-Shell ability. It requires 90 LP and the Shell Shield license to equip.
The Shell Shield appears in the trading card game. It looks like the one from Final Fantasy XII.