For sale is reprint of Conar Tube Tester Model 221, 223, 224 Tube Test Data Book. Manual is 31 pages long dated January 1st 1978. Test data was released by Coletronics Service and is newest data for Conar tube testers.  Real Paper Manual. Quality Printed and Comb Bound. Printed from available copy or scanned from original at 800dpi, restored in Photoshop, Laser printed on premium acid free paper, they will serve for years. Most manuals Include foldout of Circuit Diagram. Cover page printed on Cover Stock.