These covers come standard with a continuous insulated "hinge seal" to prevent heat
from escaping from an area most people don't even think about. Most other covers have what
are called "fingers" or "steam sealers" (below). These are two pads
that are placed on the underside of the cover, at the ends, between the two halves to
prevent steam and heat from escaping when the cover is installed on your spa. If you turn
one of these covers upside-down you'll actually see that they also push the two insulating
halves apart (below), leaving as large as a one inch gap between the two halves. This
is equal to having a hole the size of a basket ball in your cover, your INSULATING
cover!