Spun reducers are machine formed in standard sizes from 3 inch O.D. to 2 inch O.D. thru 32 inch O.D. to 30 inch O.D. Constructed of 20 gauge galvanized metal, Spun Reducers' collars are small end and length varies between 1.5 to 2 inches. Collars also measure 1/16 less than even inch outside.Most Reducers have over all length of approximately 8 inches.