Safely attach crib mobiles with J.L. Childress easy-to-use crib mobile attachment clamp! The crib mobile attachment clamp features large rubber pads that grip the crib railing and protect your crib from scratches and damage caused by post-and-knob style arms. Use the clamp as a replacement for post-and-knob styles that don"t fit on all cribs. The crib mobile attachment clamp fits onto both traditional and convertible cribs, including baby"s dream and specialty and decorative cribs. The clamp opens to 2 inches wide and the arm features a convenient safety button to lock the clamp in position. The quick-attach clamp is easy to use simply push on the lever to open the clamp and slide it over the crib railing. The clamp will automatically adjust to the width of the railing. It measures approximately 18 inches high. Extra assembly required for mobiles with closed loops on the top of the music box instructions included. Clamp is not for use on round or soft rails.