Bypass Jack; Thumbscrew - Boss TU-2 Chromatic Tuner Owner's Manual

11. BYPASS jack

Connect your amp or another effect unit to
this jack.
This jack will always output the signal from
the instrument connected to the Input jack.
Use this jack if you want to be heard while
you tune.
12. Pedal switch
Pressing this switch will turn the tuner on/off.

13. Thumbscrew

When this screw is loosened, the pedal will
open, allowing you to change the battery.
For the procedure, refer to "Changing the
battery" (page 23).
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