Set of 4 heavy-duty matching 8" diameter industrial casters, manufactured by Bassick as model 8-898. The Bassick company was founded in 1878 and in 2001 acquired by the Shepherd Caster Corporation. Two have swivel tops and two have stationary tops. Wheels of this size typically cost $325-600. It appears this exact model is no longer produced so we cannot be sure of the weight capacity but based on other similar models guess these to be in the 1,500-1,700 lb range, making it suitable for for heavy carts and machinery on concrete floors.