This soft-side waterbed set is part of our winner's collection. Each model in the Strobel winners collection is named after a Kentucky derby-winning horse and features fabric-covered inner support rails made from soy-based foam, a soft-side heater (for deep fill and extra deep fill models only), and a premium strobel soft-side waterbed mattress. Strobel’s winner's collection is broken into 3 model categories: shallow fill (4” fill depth using tube system), deep fill (6” fill depth), and extra deep fill (8.5” fill depth). When you choose a Strobel soft side waterbed you too will be a winner! This “day star” soft-side waterbed mattress top the only set is a deep fill model. Strobel’s hydro-support 1200 mattress (included with this set) is semi-waveless with 2 layers of internal, full-body support fiber for partial wave reduction. The mattress comes with Strobel’s patented leak-proof double wall technology guaranteeing your mattress from messy water leaks and offering you peace of mind. The hydro-support 1200 waterbed mattress is uniquely designed with a deep molded surface for pressure reduction and conforming comfort, added lumbar support, and 4-way tethered corners to prevent internal shifting. Strobel waterbeds do not require toxic flame retardant chemicals like other mattresses to comply with federal fire safety regulations.