ER400 Super Waveless Softside Waterbed Mattress Bladder — S-Class Series
What is a Softside Waterbed? A softside waterbed bladder sits inside a foam rail system with a slanted inner edge — giving it the look and feel of a regular mattress while delivering the therapeutic benefits of a waterbed. Unlike a hardside waterbed, a softside fits inside any standard bed frame. However, the frame must be able to support the weight of a water-filled mattress — not all standard frames are rated for this. We offer compatible wood foundations and metal bed frames for customers who need a weight-rated option.
Softside bladders are designed specifically for softside foam rail systems and are not interchangeable with hardside bladders. Dimensions shown reflect the outside measurements of the complete bed system the bladder is designed to fit — not the bladder itself.
This listing is for the bladder only.
ER400 Specs
Series: S-Class
Wave Level: Super waveless — significantly reduced motion; the ER400 dampens the majority of wave action while still retaining some of the classic waterbed feel
Construction: 24 mil purple PVC exterior; seven comfort layers including three lumbar support layers and tethered wave control
Best For: Sleepers who want substantial wave reduction and back support while retaining some of the classic waterbed feel
Single or Dual?
Single: One full bladder — one heater, one temperature, one firmness level across the whole bed
Dual: Two separate bladders (left + right side) with a foam divider included — allows each sleeper to set their own firmness and temperature independently
⚠️ Two heaters required for Dual: One heater per bladder, placed under the safety liner. A single heater spanning the gap between two bladders leaves an uncovered section that can overheat — potentially melting the liner and bladder, causing leaks, or starting a fire.
The bladder alone is not a complete sleep system. You’ll also need a foam rail and cover system for the bladder to function properly. Our Softside Waterbed Cover System includes foam rails, a cover, and a fitted safety liner — everything except the bladder.
There is no comparison to a Sterling Softside. We have tried multiple brands (and types) of sleep systems. By far, Sterling Softside waterbed mattress outweighs any type of mattress system.
This is our second order due to age of our first mattress system. Once you sleep on a Sterling waterbed, there is no return to a regular mattress. The back support is beyond imaginable. I have high body heat when sleeping. The Sterling Waterbed system zeroes this issue out which makes sleeping at night quite snug.
Excellent experience from setup to sleeping! Had a soft side waterbed 8 years ago & loved it. So after experiencing the memory foam, decided to go back to a waterbed. Anton was very helpful with answering my questions & recommending the right choice in our bed. Thank you!!
review if super waveless softside waterbed mattress(s)
I like the mattress and customer service was very quick and courteous. I ordered two new mattress bladders and received them within two days. The reason that I had to order the bladders was that one sprung a leak and I have no idea how or where it was. I only know it sprang a leak because the liner did not hold the leaked water and the frame was wet. The sterling system is good - if it didn't spring a leak. Mattresses were about 4-5 years old.
United States