Sony D-CS901 Operating Instructions Manual page 5

CD player (inside)
q
G-PROTECTION
switch
(page 16)
a Battery compartment
(page
22)
Using the hand strap
During active uses, use the supplied hand strap.
1 Pass the strap through the hooks.
2 Put your hand between the player and the strap, then adjust the length of the strap and fix it
using the Velcro tapes.