Check the listing for details. Jackson 648 Calibration Tube for Jackson 648 Family. Condition: Used. Listed at 11.24 USD. You are buying a: Jackson 648 Calibration Tube for the Jackson 648 FamilyTESTED ON A CALIBRATED JACKSON 648S TESTERTHIS TUBE WILL WORK ON ALL VERSIONS/MODELS OF THE JACKSON 648 FAMILY648, 648A, 648P, 648R, 648S, 648-1& 648-1TThis tube is ONLY for calibrating the Jackson 648 family Sold as is as Pictured as Described Please leave 5-star eBay Feedback! This is very important! We strive to make this happen! We fix all problems, please contact before leaving any feedback to let us fix the problem! We want all buyers satisfied! All orders are shipped within 1 business day of payment clearing! Check out my other items! Be sure to add me to your favorites list! Please Do Not Leave Any Kind of Negative Feedback Without First Contacting Us, We Will Fix Any Problem If There Ever Is Any. Thank You and Good Luck! Please email with any questions.