XRAY has released T4'21 Aluminium Extra Flex 2.0mm Swiss 7075 T6 under category
Aluminum T4'21 framework with exclusive cutout openings for increased flex. This chassis is recommended for low traction carpeting songs and high traction asphalt tracks. (perhaps not motivated for high- and very-high carpeting traction tracks by which either the #301005 or #301006 framework are more effective). Fits T4'21