S3 PISTON 300 "A" size

NEW GG PART NUMBER MT710003010  (but fits all Gassers from 2003 onwards)
same as PI-SH-TR305-A SHERCO 305A piston 
SHERCO Part number 3218 (Sherco ST 300/305 from 2011 onwards)
TRS ONE 300 A piston 70462 78.95mm

and Vertigo 300's

also fits Beta 300 EVO

Size A 78.95mm
Size B 78.96mm
Size C 78.97mm