Description from Carlysle Manufacturing Company

Includes:

• One solid walnut shelf with a natural finish.  The shelf 6″ deep,  1″ thick and  either 27″, 36″ or 45″ long as requested below (prices do vary).  Shelf includes a picture groove to help stabilize pictures and framed objects.
• Two steel support rods treated with a natural finish.  Rods are available in varying lengths which can be specified below.  Rod lengths are measured from the top of the mounting hook.  
• Two pre-installed locking collars mounted on the underside.  These allow for easy height adjustability along the support collars.
• A 5/32″ allen wrench and level for installation.