Factory Shorthorns utilized a little bit of everything. The first five in 1962 used the 15WK woofer, and a couple more used the SAHF mid. Otherwise the standard compliment in 15" models until the product's demise in 1967 was K33J/K55V/K77. Earlier, the Stephens 103LX and EV 15WK appeared sporadically. Prior to the K55, the University SAHF was standard, and a few 4401 tweeters preceded the K77. It was all over the map on this "bargain basement" model. Quite a few came back in for factory upgrades, and some were sold w/o drivers.