Grappler Fixed

You’ve developed the skills necessary to hold your own in close-quarters grappling. You gain the following benefits:

• You have advantage on attack rolls against a creature you are grappling.
• You can use your action to try to pin a creature grappled by you. To do so, make another grapple check. If you succeed, you and the creature are both restrained until the grapple ends.
• The pinned creature can take verbal and mental actions, but cannot cast a spell that requires somatic or material components unless the material component is already in hand. 
• In order to cast a spell, the creature must succeed on a DC 10 concentration check. If their concentration is broken, the spell dissipates without taking effect and they expend the spell slot.