ER-Collet Holder for ER-Collets ER08,ER11,ER16,ER20,ER25,ER32,ER40 All holders will be supplied with a clamping nut. Runout accuracy ER-collet holder < 5µ Available in several shank diameters with radial inner coolant lead in (IK), with clamping flat throughout (WD) or with clamping flat stepped (FL).