See also:

Trailer brakes
If your trailer is equipped with a braking system, make sure it conforms to federal and/or local regulations and that it is properly installed. Never connect a trailer brake system directly ...

Maximum Gross Vehicle Weight (GVW)/Maximum Gross Axle Weight (GAW)
The GVW of the towing vehicle must not exceed the Gross Vehicle Weight Rating (GVWR) shown on the F.M.V.S.S./C.M.V.S.S. certification label. The GVW equals the combined weight of the unloade ...

Never leave these keys in the vehicle.
Additional or replacement keys. If you still have a key, the key number is not necessary when you need extra NISSAN Vehicle Immobilizer System keys. Your dealer can duplicate your existing key. ...