If your gonna buy piston rings, buy RIK brand. RIK brand has the best quality among the three NPR, TP and RIK. RIK quality is best, as it supplies to major car makers such as Daihatsu, Hino, Honda, Isuzu, Mazda, Mitsubishi, Nissan Diesel, Subaru, Suzuki and Toyota as Original Equipment manufacturer. and also RIK is no. 1 largest manufacturer and no.1 brand in Japan, the 2nd largest piston ring manufacturer even OEM to foreign brands such as AUDI, BRIGGS & STRATTON, BMW, CATERPILLAR, DDC, FORD, JAGUAR, MAK, MAN, SEMT, Volkswagen, WARTILA, New Holland, KS and MAHLE.
My friend informed me that RIK performs better than other brands.