Check the listing for details. KNOB & VERNIER TUNING ASSEMBLY (TEN-TEC 422 CENTURION LINEAR AMPLIFIER). Condition: Used. Listed at 150.00 USD. This listing is for a one (1) complete knob and vernier tuning assembly for the Ten-Tec 422 Centurion amplifier. This will work on either the Load or Tune position.This vernier gives about 5 to 1 reduction on the output shaft. This in effect gives 2-1/2 revs for a full half turn of a tuning capacitor in the Centurion amp which is ideal for capacitance adjustment.The output accepts a 1/4” diameter shaftMounting requirements are simply a 0.810" diameter hole thru your front panel to allow the brass flange to pass through, then two small 1/8” holes for the mounting screws, spaced 1-1/4 inches apart (5/8” hole pattern radius). This is an easy turn key way to put a smooth and professional tuning adjustment on your amplifier, antenna tuner or anything you need to adjust with fine precision.You will receive the EXACT item shown in the picture. Thanks for looking!!! _gsrx_vers_1634 (GS 9.6 (1634))