1 pair of passive subwoofers drivers in a custom-made enclosure. No amplifier is included. This subwoofer driver is an absolute apex-predator. At the time that I purchased them (in the US) they were the highest output most linear subwoofer driver that Klippel labs had ever measured! I have two of them currently mounted in an extremely solid (braced), sealed, dual opposed enclosure with a net internal volume of 8cubic feet or 227 liters. Rectangular in shape. Each driver weighs in @ a whopping 34kg and features single piece titanium cones. So, I would guesstimate that the enclosure with both drivers is somewhere around 115kg in total. Take just the sub drivers or keep them in the enclosure. The price doesn't change. They will require pro sound amplifiers to give them adequate power. The drivers are in good shape and work great. The stock provided gaskets are gone. I have drilled a couple of extra holes in the mounting frame for additional mounting screws. Nothing that isn't solved with new gasket tape. Moving back overseas and these are too much to ship back. Obviously, p/u is necessary. If you want to move some air... and do it accurately.... this is your opportunity. Something that you will never find again on these shores. https://web.archive.org/web/20070605003549/www.tcsounds.com/lms5400.htm