Precision Tube Tester 612 and 614 Operating Instructions Sorry, this product cannot be purchased. $7.99 Category: Precision Apparatus Company Related products Precision Tube Test Data for 10-12 10-15 10-20 10-22 10-54 Tube Testers 2-1-1976 $9.99 Read more Precision Tube Tester 10-54 Operating Instructions $8.99 Read more Precision Apparatus EV-20 Vacuum Tube Multi-Meter Manual Read more Precision Apparatus E-300 Sine-Square Wave Signal Generator $8.99 Read more