These collets are used to securely hold your end mills into your spindle during milling. ER-32:Length: 40 mmDiameter: 33 mmRange: 1—12 mmER32 Collet - 7mmSKU: 172Quantity*Add to CartRETURN & REFUND POLICYNon-Refundable SHIPPING INFO2-3 Days for Available stock Items 7-14 Days for Out of Stock Items