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 10-60 Tester $9.99 Read more Precision Tube Test Data for 10-12 10-15 10-20 10-22 10-54 Tube Testers $9.99 Read more 1953 Precision Apparatus E-200 Servicing by Signal Substitution Manual $10.99 Read more Precision Tube Tester 10-60 Operating Instructions $9.99 Read more