Sony PCG-F640 VAIO User Guide (primary manual) User Manual page 55

1 There is a Release lever on the bottom of the weight saver. To remove the
battery pack, slide this lever in the direction of arrow 1, then slide the
RELEASE lever on the bottom of the computer in the direction of arrow 2.
Multipurpose bay release levers
Remove the weight saver, and then pull out the battery pack.
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3 Reinsert the weight saver. See "Using the Weight Saver" on page 56.
Using a Second Battery Pack
Arrow 1: Weight saver Release lever
Arrow 2: RELEASE lever
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