For sale is a pair of vintage Altec 501-8B crossovers. These are my favorite 500 hz crossovers for A7 system. Much better than the 8A version which are a dime a dozen. These are fully functional but sold as is since capacitors can drift out of spec with age. They have all original caps and parts inside and are not modified in any way. The serials on these are far apart (4xxx and 1xxx) but still work as a pair as I used in past. Will ship with great care.