Skylon Instec shafts (doz)The Instec features the same 24 ton carbon construction as the Brixxon and Radius shafts but with a + 0. 005in straightness tolerance and 5. 2mm internal diameter (ID5. 2). Supplied as a set of 12 shafts with inserts and X size nocks included. Points are sold separately. An ideal arrow shaft for outdoor hunting for compound archery. 300 350 400 500 600 700 Skylon Size Selection Chart (PDF)