This auction is for a copy of a set of plans to build a JBL 4520 (C55) Bass-Scoop Rear Loaded Horn.
The plans are six (6) pages with a assembly instructions.
This is a rear loaded horn for dual 15 inch drivers. (JBL recommends a D130 , 150-4C or 2205 PRO driver)
The exterior dimensions of the 5420 (C55) cabinet are given as 50 1/2" H, 35 3/4" W and 29 3/4" D.