Parts of a Seatbelt

A three-point seat belt on a car seat, then its buckle and retractor close up.

Parts of a Seatbelt

Name Date

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1 2 3 4 5 6 7 8 9
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Write the name of each numbered part.Answer key

  1. Shoulder belt
  2. Lap belt
  3. Buckle
  4. Latch plate
  5. Retractor
  6. Anchors
  7. Pretensioner
  8. Spool
  9. Pendulum

Drawn for this site by script, 2026-09-27. Licence: own work.

Each numbered ring is a button. Use the arrow keys to move between them and Enter to choose. Names are read out in Study, and once a part is answered.

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All 9 parts on the diagram

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Start here: 6 main parts 6

  1. Shoulder belt Part of the webbing that runs diagonally across the chest and shoulder. The US standard calls it the upper torso restraint.
  2. Lap belt The part of the webbing across the hips, which holds the pelvis. The US standard calls it the pelvic restraint.
  3. Buckle The quick-release fastener on the inboard side. The latch plate clicks into it. Pressing its button lets go.
  4. Latch plate The metal tongue that clicks into the buckle. It slides along the webbing.
  5. Retractor Stores the spare webbing and winds it in. It sits at the foot of the pillar. An emergency-locking retractor locks in a crash.
  6. Anchors The fixing points that pass the belt's load into the car's structure. Here one is high on the pillar and one at its foot.

The locking parts: 4 3

  1. Pretensioner Pulls the belt tight in a crash and takes out the slack. It fires a small charge to do so.
  2. Spool The drum inside the retractor that the webbing winds round.
  3. Pendulum A small swinging weight in the retractor. Sudden braking or a rollover swings it out of place, which locks the spool.

How this list was compiled: Read 2026-09-27. (1) 49 CFR 571.209, Standard No. 209, Seat belt assemblies, via Cornell LII, https://www.law.cornell.edu/cfr/text/49/571.209 : definitions of webbing, buckle (a quick release connector), retractor (a device for storing webbing), emergency-locking retractor, pelvic restraint and upper torso restraint. (2) 49 CFR 571.210, Seat belt assembly anchorages, via Cornell LII, https://www.law.cornell.edu/cfr/text/49/571.210 : a seat belt anchorage is any component that transfers seat belt loads to the vehicle structure. (3) Wikipedia, Seat belt, https://en.wikipedia.org/wiki/Seat_belt : the webbing, the tongue (latch plate) and buckle, the shoulder harness and lap belt, inertial reels and locking retractors, a vehicle-sensitive lock based on a pendulum swung by rapid deceleration or rollover, pretensioners that fire a small charge to tighten the belt in a crash, the central drum of the mechanism. Licence: own work

The drawing: Drawn for this site by script, 2026-09-27. Own work, nothing traced. Licence: own work

How it works

These are the parts of a seatbelt on a three-point belt seen from the front, with the buckle and retractor drawn again close up. Start with the 6 main parts.

Read the full guide

The belt

One length of webbing forms two belts: the shoulder belt across the chest and the lap belt across the hips. The latch plate slides on it and clicks into the buckle. Anchors fix it to the car.

How it locks

The retractor winds spare webbing onto its spool. In a sudden stop a pendulum inside swings and locks the spool, and a pretensioner can pull the belt tight in a crash.

  • The US safety standard names the lap belt the pelvic restraint and the shoulder belt the upper torso restraint.

Questions and answers

What is the metal part of a seatbelt called?

The latch plate, or tongue. It slides along the webbing and clicks into the buckle.

What makes a seatbelt lock?

The emergency-locking retractor. In many belts a small pendulum inside swings when the car brakes hard or rolls, and that locks the spool so no more webbing pulls out.

What is a seatbelt pretensioner?

A device that fires a small charge in a crash to pull the belt tight quickly, taking out the slack before the body moves forward.

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