Quick view 36" x 10" Aluminum Toroid, Seamless 36" x 16" x 10" Aluminum Toroid, Seamless This heavy duty, seamless toroid is the one used in our Plasmasonic 3.0 and Reference Design 3.0 systems. It is made of 99% pure (grade 1100-O) aluminum, heavy duty, and welded with no visible seam. ...