This is a Ruland shaft collar with a bore size of 1-15/16 inches. The collar is black oxide and it is made of lead free steel. It is ideal for industrial automation & motion controls. The brand is Ruland Manufacturing and the model number is SP-31-F. This shaft collar is perfect for mechanical power transmission and is categorized under Shaft Collars & Clamps, Mechanical Power Transmission, Industrial Automation & Motion Controls, Business & Industrial.