Conversion set for T4'20 to improve it towards T4'21 Aluminum Solid variation. Includes all necessary elements including aluminum solid framework, graphite top deck, body upstops & battery pack adj. width meals, composite 4° c-hubs for human anatomy upstops, composite bumper top owner brace, composite adj. battery power holders & backstops, springs, ECS drive shafts 52mm, aluminum steering plate 8mm, aluminum gear tensioner, aluminum motor mount, aluminum framework brace, aluminum straight back suspension system system, holders with centering pin, steel solid drive shafts as well as other components,