Tyros 4 twinset. There are two or three mfg. with kits for the 2 keyboard organ setup. This link, http://www.youtube.com/user/cvp409gp#p/u/28/9hOjnyHyl-c, is to a you tube assembly video for one of the kits. The mfg.'s website with photo's and prices. http://www.muziekhuisdera.nl/show_product.php?prod_id=838&selectie=64&ag=Keyboards
regards, chuck