California King 72 x 84 Semi Waveless Waterbed Mattress vinyl 24 Mil Vinyl with Extra Reinforced Corners If you have want the school semi wave mattress then you just found it. Manufactured by Classic since 1971. Our semi waveless mattress has about 8-10 seconds of movement Mattress comes with a 4oz bottle of Premium Clear Bottle Conditioner & Fill Kit. Don't settle for less.