This sign holder clamp is great for any sales floor. The mount fits round, square and rectangular tubing. This sign holder clamp allows for signage to be placed in various locations on the sales floor. The mounts versatility will benefit the sales floor. The clamps ability to attach to a variety of objects is great for show casing merchandise. Heres how the system works: 1) Choose size and style of frame that best suits your sign. 2) Decide which type of clamp will work best for your fixture: magnetic, spring, or C-clamp. 3) Complete the holder with the appropriate stem fitting and length.