Zenoah 32mm piston. New-style optimised piston as featured on 'red cap' engines for use with the .8mm piston ring. 
PMW part # 4320
Zenoah part # T2071-41110
FG part # 07308/09

Stock Part on the 
G230RC  G240RC   G231PUH  G231PUM

Use Zenoah pistons with Zenoah top ends, CY top ends should use CY pistons