bucket seat: front view
Bucket seat: upholstered and adjustable seat that envelopes the occupant’s body, keeping it in place during turns and providing greater comfort.
sliding rail 
Metal part along which the seat moves forward and backward.
sliding lever 
Handle for moving the seat toward or away from the dashboard, in relation to the passenger’s height.
shoulder belt 
Strap crossing in front of the passenger’s thorax, from the shoulder to the hip.