NOS Wellworthy Piston Ring Set R23020 +.020 Triumph Trident T150 T160 BSA RocketNOS Wellworthy Piston Ring Set R23020 +. 020 Triumph Trident T150 T160 BSA Rocket 3 This is a New Old Stock (NOS) genuine Wellworthy piston ring set, specifically manufactured in the UK for vintage British 750cc Triple engines. Wellworthy was the original equipment manufacturer (OEM) for many Triumph and BSA components, ensuring a high quality fit and period correct metallurgy for your restoration. Product Specifications Brand: Wellworthy (Genuine