Carmex Extension With Internal Coolant Bor - for Indexable Milling Holders - E25M12L100Carmex Extension With Internal Coolant Bore for Indexable Milling Holders (E25M12L100) is a precision threading extension that lets CNC mills cut external and internal threads in a single pass using helical interpolation. Designed for machinists and job shops, it delivers reliable, versatile threading with minimal setup and downtime. Internal coolant bore: Delivers coolant directly through the tool for cooler cutting and extended insert life. One pass