one is the 4648, using a pair of 2226H (8 ohm) woofs, with a system z of 4 ohms. Another, the one on the tent sale for $220, is the 4648A-8 using a pair of 2226J (16 ohm) woofs for a system z of 8 ohms (hence the -8 at the end of the model number?). Another version has the first woofs, with a network also. It appears to me that you have a pair of 16 ohm 2226J's coming...maybe Wayne can suggest proper xover values if you need them later. Sam