40 thou oversize low drag slipper type pistons for modern day compression ratios and unleaded fuel.
Typically installation will result in a minimum 8.8:1 compression ratio but on some pre 1984 Metro versions it was higher.
Current pistons differ from the 60s originals, improved with a "low drag" slipper skirt design and a shorter lighter wrist pin.
Wrist pin height is 1.4689", crown has 8cc dish, and they have two 1.5mm compression rings and a 4mm oil ring.
From the top ring to crown these measure about 7mm and the high compession P21253 piston have 10mm gap from top ring groove to crown.
Ringset is
R35960-40.
Sold singly,4 per engine required
Now Nural stamped 87-521711-00
AE Hepolite is now owned by Federal Mogul and trademarked "Nural".