Front opening is 3.5" Dia. Rear is 9" Dia. Expansion horn is 7.25" Dia. The length is 21.5". Compatible netting size is 12, 14, 16, 18, and 20. Weighs 6 Lbs. Dimensions: 21.5"L x 10"W x 10.75"H. See page 247 of our 2011 catalog for details.