Juniper MX2020 Hardware Manual page 272

WARNING:
continually press and hold the latch while removing the fan trays.
5. Place each component on an antistatic mat resting on a stable, flat surface.
CAUTION:
Figure 94: Removing Upper Fan Trays
Figure 95: Removing Lower Fan Trays
The fan trays use a double latch safety mechanism. You must
Do not stack fan trays on one another after you remove them.
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