SILV-O-LITE Hypereutectic 1/2 Dish pistons for Avanti R-1 & R-2. U.S. made, available in standard size and five over sizes,

.020, .030, .040, .060, .080

1/2 Dish-top pistons on an R-1 engine will lower the compression ratio from 10.25:1 to about 9.00:1

Sold in sets of eight.