My P77 came from Brian and John Garrott back in the mid ’80’s and was fitted with their Microscanner stylus - which I believe is a MicroLine of some sort. I never got a replacement stylus, just moved onto something else.
Brian and John never used Boron cantilever in their Dynamic Coil cartridges for some reason and i believe they knew what they've been doing to make P77 sound sweet with aluminum cantilever.
Frankly I’m surprised the SAS stylus works at all because the carrier looks nothing like the original Garrott.....but I was encouraged by others that had tried the SAS on the P77 variants.
I think that SAS replacement originally was made for Shure cartridge.