A retaining device for securing one or more accessory racks to a base rack on a vehicle is provided herein. The device comprises a housing member that extends through the one or more accessory racks and into the base rack, a head, secured to the housing member that engages one or other of the racks, a detent that engages the other of the racks, and an engagement mechanism that extends the detent and pulls it toward the head. The device may further comprise a lock that secures the detent in a clamping position. The lock may comprise a ratchet and pawl arrangement defined by first and second levered tabs disposed on the head, the first tab being operably connected to the engagement mechanism. An ATV comprising one or more accessory racks secured to a base rack by a retaining device as described herein is also provided.