Sony Walkman D-F21 Operating Instructions Manual page 5

CD player (inside)
qf ESP switch
(page 13)
qg AVLS switch
(page 14)
CD player (rear)
qh E13/2 model:
MONO/ST (stereo) switch (page 10)
Other models:
LOCAL/DX switch (page 10)
qj STEP switch
(page 12)
qk Battery compartment
(page 17)
5