Straight Shank – Mini Extension | The Indexa ER Collet chuck is manufactured as part of Europe’s most popular collet system. The collapsing collet design can be used for a range of diameters and maintains concentricity for drilling and milling. Long reach options are also available to give access into deep recesses. Balanced to 12,000rpm. Max Tir 0.010mm. (BT BT-MAS 403)