Hi Bille, from the manufacturer’s website for the GPS SD…
“The GPS SD has a built in low power wireless interface for connecting compatible accessories. The list of Flymaster wireless accessories is the most complete on the market. Already available for the GPS SD are the HEART-G, TAS and M1.”
Where TAS stands for “True Air Speed” and this is the related info: TAS probe.
From what I hear, most of the gear may already be spoken for, but the seller will finalize after returning in a few days. One can still contact the seller to get in line in case previous arrangements fall through. Good luck.