ERSE's PRO Zx line of passive crossovers are built with high quality ERSE components to insure clean pure sonic quality. The Linkwitz-Riley design can be used with a 4 ohm or 8 ohm low frequency load via the selectable jumper. Great for D'Appolito designs which utilize two woofers and one tweeter. IQ coils are utilized in the low pass circuit to insure a low D.C.R and efficient clean power transfer. Premium ERSE metallized polyester caps made from Dupont film insure accurate reproduction of the low and high frequency circuits. Each PRO Zx crossover is built on a premium PC Board backed by a rigid hard board to insure durability. Brass eyelets are pressed in all four corners to allow for easy rugged mounting. An original ERSE design!