Narrow Car Seat Booster

car seat
A car seat is the chair used in automobiles. Most car seats are made from cheap, but durable materials, made to withstand as much beating as possible. The material for these seats is usually used for the back of the seat, as well as the part where one's posterior goes.
Soup is the second album by the American rock band Blind Melon, released shortly before vocalist Shannon Hoon's fatal drug overdose, making it his final album with the band. Thematically, the album is much darker than the band's multi-platinum debut.
a seat in a car

booster
promoter: someone who is an active supporter and advocate
supporter: a person who backs a politician or a team etc.; "all their supporters came out for the game"; "they are friends of the library"
A person or thing that helps increase or promote something, in particular
A source of help or encouragement
a thief who steals goods that are in a store
A keen promoter of a person, organization, or cause

narrow
A narrow channel connecting two larger areas of water
not wide; "a narrow bridge"; "a narrow line across the page"
a narrow strait connecting two bodies of water
make or become more narrow or restricted; "The selection was narrowed"; "The road narrowed"