Sony hdw-730 Operation Manual page 296

Attaching a battery pack
1
Press a battery pack against the back of the camcorder, aligning the
side line of a battery pack with the line on the camcorder.
5
2
Slide a battery pack down until its "LOCK" arrow points at the
matching line on the camcorder.
5-2
Chapter 5 Setting Up the Camcorder
Back of camcorder
BP-L60A/M50/
M100
Align these lines.
"LOCK" arrow
Matching line on
the camcorder