Quick Release Bike Seat

quick release
(of a device) Designed for rapid release
A joint type which makes it possible to screw and unscrew the butt and shaft very quickly; faster than standard threads.
A clamping mechanism used to hold on wheels and sometimes used to secure seatposts in the frame. Quick releases make it easy to remove wheels for storage or flat-tire repair. You'll also find quick releases on seatposts and sometimes other parts such as handlebars on some folding bicycles.
A quick release skewer is the rod, threaded on one end and with a cam assembly on the other, a part of the quick release mechanism, a lever operated cam system used with a hollow axle for securing the wheels on a bicycle.

bike
motorcycle: a motor vehicle with two wheels and a strong frame
A bicycle or motorcycle
bicycle: ride a bicycle
bicycle: a wheeled vehicle that has two wheels and is moved by foot pedals

seat
show to a seat; assign a seat for; "The host seated me next to Mrs. Smith"
be able to seat; "The theater seats 2,000"
The roughly horizontal part of a chair, on which one's weight rests directly
A sitting place for a passenger in a vehicle or for a member of an audience
a space reserved for sitting (as in a theater or on a train or airplane); "he booked their seats in advance"; "he sat in someone else's place"
A thing made or used for sitting on, such as a chair or stool