It has an independently - wrapped pocket coil spring system, which makes the sofa comfortable while sitting for a long time. (wayfair.ca)
The activity jumper's four point spring system makes it very sturdy and safe, so parents do not need to fear about it tipping over. (jumperooforbaby.com)
Produced in mirror polished stainless and mild steel, the traps are fully operational with enlarged spring systems. (upstreamgallery.nl)