MSI PRO Z790-A WIFI DDR4 Manuel D'utilisation page 33

Installing M.2 module into M2_2 slot
1. Secure the supplied M.2 standoff according to your M.2 SSD length if need..
2. Insert your M.2 SSD into the M.2 slot at a 30-degree angle.
3. Secure the M.2 SSD in place with the supplied M.2 8.5H screw.
8.5H screw
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Standoff
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Installing M.2 module into M2_3 & M2_4 slots
1. Loosen the screws of M.2 Shield Frozr heatsink.
2. Lift up the M.2 Shield Frozr heatsink and remove it.
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30º 30º
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