This innovative TERO AK7 shafts are new patent system from CUESOUL,well-designed built-in spring telescopic and rotation combo system(combine with AK4 flights),perfect for soft tip and steel tip darts.Rotation(without wobbling)any allows each dart to be more closer together,avoids flights ripped out caused by hitting previous dart,telescopic prevent dart's deflection when hit the previous dart,both assure the flights more durable use. This TERO system help your darts fly more stable and true,it will keep you from bend down and pick up flights in the heat of a dart game. Features: Octagon shape on edge of shaft screw help to tighten or loose the shaft more easily than common one. Extra twin strengthen line moulded at the end of screw ,holds the shaft more incredibly tight to the barrel,even in each shoot. Set include 4 pcs TERO shafts. Total 4 colors available(black/white/red/yellow),with modern and attractive pattern design on flights,you could also mix-match casual with your personal style. Size: S: combine with TERO AK4,length 21.5mm(about 17/20 inches),measured from the edge of the screw to the joint between the flight and shaft.Total 61.5mm(2-2/5inches ,not include screw) Weight : TERO AK4 flight,0.8g/pc ,TERO AK7 shaft,0.7/pc, combo weight,1.5g M: combine with TERO AK4 ,length 26.5mm(about 1-1/25 inches),measured from the edge of the screw to the joint between the flight and shaft.Total 66.5mm(2-3/5inches ,not include screw) Weight : TERO AK4 flight,0.8g/pc ,TERO AK7 shaft,0.8/pc, combo weight,1.6g L: combine with TERO AK4 ,length 33mm(about 1-3/10 inches),measured from the edge of the screw to the joint between the flight and shaft.Total 73mm(2-7/8inches ,not include screw) Weight : TERO AK4 flight,0.8g/pc ,TERO AK7 shaft,0.9/pc, combo weight,1.7g