I dont like using company descriptions too often, but I think SA describes this in better terms than I could, enjoy - C
"One day, long ago, in a kingdom far, far away, we dreamed up a line that would sink, but not sink too much, one that would simply hover beneath the surface. Fast forward thousands of years and the SONAR Stillwater Hover sinking fly line was born. Built with an extra-slow sink rate, the Hover is downright nasty when it comes to fishing streamers with a slow retrieve. It’s a legend, at least in our own minds."
In other words, this line will get your bugs deeper than a midge tip but not as quickly as a true intermediate (the Hover sinks at 1 inch per second (ips) as compared to the SA full intermediate at 1.25 ips).
Based on the popular MPX taper, overweighted by a full line weight for multiple flies and long leaders
Extra-slow sinking hover (1 ips) for fishing the film
Pale Green / Surf color combo (see line diagram image)
Advanced Shooting Technology (AST)
SA line ID
'Sonar' Sinking Technology
for more information on SA's proprietary technologies: https://www.scientificanglers.com/technologies/