Shortway 45* Angle 121SD Equivalent length 5' supply or return. Size 14" x 8" available 6 per box. Sizes 8" x 8", 10" x 8", 24" x 8"; available 4 per box. Sizes 22" x 8", 26" x 8" - 30" x 8", 10" x 10" - 24" x 10"; packed to order.