It looks like a "Wally Flap". IMO not much benefit. The GSA allows some airflow (and water) between tank bottom and cylinders but a heck of a lots more comes off the back wheel. A Mudsling is more effective than a hugger. Removing the shovel also helps as it throws spray forwards, but you will need a fender extender on the number plate bracket.
A hugger like the old Britten 1000 would do a better job. It went well over the back and top sides of the wheel so spray could not throw out sideways.
Nobody makes anything like that. All you will find are fashion accessories that offer next to no useful protection from dirt & spray.
I don't know who makes them, but if they replicate the lower fairing of an RT, then they should work.
ie. Clean and dry boots when I ride an RT in the wet, but wet boots when on the GSA.
My legs and boots get wet from the back wheel. It's a lot better with the MudSling. Some wet gets through between petrol tank and cylinders. But nothing like most bikes.