Two (2) Aluminum Flanges included with purchase. Specify the length between flanges - available from 1-1/2" to 6". Please specify in notes section during checkout the size spacer required. Aluminum flanges and spacer are used to space wheels on combination, and arbor units. Now made out of 6061 Aircraft aluminum! Flanges are 3" in diameter with 1" arbor hole. Special arbor hole sizes can be ordered by contacting us.