JL Childress Crib Mobile Attachment Clamp – Now you can safely and easily attach crib mobiles to your baby’s crib with the easily assembling Attachment Clamp Clamp opens 2″ wide and also features a safety lock button to lock the clamp into position Measures approximately 18″ high when assembled Safely grips to the railing without causing any damage due to the rubber padded clamp Simple to attach – Simply push on the lever to open the clamp and slide over the railing to attach The JL Childress Crib mobile attachment is designed to fit most traditional and convertible cribs.