Omega Products ER40 Collet Coolant Sealed Standard Precision - 10 Micron Run-Out -14mmStandard Coolant Sealed Collets (<10 accuracy) Rubber Seal Clamping Range 3 26mm our newer versions have no rubber seal on the nose. The longitudinal slots do not overlap at centre so preventing coolant loss. Do though please ensure you are using solely round shank tooling with no clamping flats to complete the seal if you are using toolshanks with clamping flats it will render these collets ineffective.