Sony PCG-F450 - Manual (Page 51)

Using the Weight Saver "
To remove the weight saver
1
There is a release lever on the bottom of the weight saver. To remove
the weight saver, 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.
2
After removing the weight saver, pull out the weight saver’s hinged
arm and fold it into the weight saver.
Arrow 1: Weight saver Release lever
Arrow 2: Release lever