APEX Code 742F Permanent Magnetic Chucks Rectangula ( Fine Pole) Features: Manufactured and supplied in matched and numbered pairs. Each Block incorporates 4 different sized Vee's thereby supporting a wide range of sizes. This enables a single block to be used as a workholding device for supporting different sized jobs. Provision for fine adjustments when setting work piece. Efficient lock provided.Fine (close) Pole Pitch For High clamping. Application: These are very useful for making and checking of cylinderical parts.