The Ac-T 5diff Calibrator is a crucial tool for ensuring the accuracy and precision of your medical devices. This product comes in a pack of 2 vials, each containing 2mL of the calibrator. Please note that this product is short-dated, meaning it has a minimum expiry lead of 30 days. This means you should plan to use it within a month of purchase to ensure its effectiveness. This calibrator is specifically designed for use with the Ac-T 5diff series of medical devices. Please follow all manufacturer instructions for use to ensure accurate results.