Seal the device carefully. On the first assembly, the screws may be quite stiff. The key goal we are trying to achieve in sealing is firm, even pressure on the silicone seal - as this is what keeps the device water-tight and dust-proof.

Ensure that the clear silicon seal is in good condition, is lying flat, and is not fouled by any plastic debris or other material.
Close the housing, and gently squeeze it shut. Foam on the lid will compress against the batteries, holding them firmly in place.
Tighten the 4 screws to uniform tightness - such that there is an even gap at all points along the interface between the base and lid.
It is a good idea to use a screwdriver start with the screwdriver on the lowest setting, and gradually increase the torque until there is a small gap between the base and lid (no need to overtighten as you risk cracking the housing)

How to install the GPS device in your car?

Getting Started