See also:

Brake booster
The brake booster uses engine manifold vacuum to assist braking force. Do not turn off the engine while driving because that will turn off the brake booster, resulting in poor braking power. The ...

Parking on a grade
Always block the wheels under both vehicle and trailer when parking. Apply the parking brake firmly. You should not park on a hill or slope. But if parking on a hill or slope cannot be avoided ...

Certification for the Handsfree system
FCC WARNING Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment. NOTE This device complies with Part ...