I am working on a line for those with depth restrictions -- NOT a true shallow woofer but something that just isn't super deep as most of our drivers are big, nasty, deep woofers. The ultra-shallow market is not something we plan to get into but I thought something shallower than the SA line would be nice. Our future "E" series line with stamped frame was not designed as a reduced depth driver either so we would have left this market totally untouched. SD-2 10" -- 4 7/8" Depth SD-2 12" -- 5 3/8"