A clip includes a body with opposite first and second legs, a movable fastener, an actuating member and a sliding axle. The movable fastener has a retaining hole defined therein for engaging with a retention module and an elongated slot above the retaining hole. The actuating member includes a curving slot and is pivotally coupled to the movable fastener via a pivot. The sliding axle extends through the second leg of the body and the elongated slot of the movable fastener to couple them together, and the sliding axle has one portion inserted into the curving slot of the actuating member. When the actuating member is rotated about the pivot, the movable fastener is driven to move relative to the sliding axle between a relaxed position and a locked position.