Parts of a Cassette Tape – Shell, Hubs, Tape and Tabs

All 10 parts on the diagram

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Outside 3

Shell The plastic case that holds the two hubs and the tape.
Window It shows how much tape is left on each hub.
Write-protect tabs Break one out and that side cannot be recorded over.

Inside 7

Hubs The tape winds off one hub and onto the other.
Magnetic tape A thin plastic film with a magnetic coating that holds the recording.
Leader A tough, non-magnetic strip at each end of the tape.
Guide rollers Rollers in the corners that steer the tape with little friction.
Pressure pad A sprung felt pad that presses the tape against the head.
Shield A metal plate behind the pad that keeps out hum.
Slip sheet A slippery liner on each side of the tape, to cut friction.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it for this part. (1) Wikipedia, text only: Cassette tape (two miniature spools in a protective plastic shell, the magnetic tape, write-protect tabs and notches, the window, the tape opening, the capstan, pinch roller and heads of the player), https://en.wikipedia.org/wiki/Cassette_tape . (2) Arthur Zuckerman, Tape Recording for the Hobbyist (1977), searched in full text at https://archive.org/details/taperecordingfor0000zuck (the shell, the hubs the tape is anchored to, tape-guide rollers, the felt pressure pad, liners or slip sheets, leader tape, the knockout tabs). (3) Cassette Recording Buying Guide (1974), searched in full text at https://archive.org/details/CassetteRecordingBuyingGuide1974USA (plastic shell, hubs, slip sheets, rollers, pressure pad, clear leader tape, the two small tabs at the rear, capstan, pinch roller). (4) Audio magazine, June 1978, searched in full text at https://archive.org/details/sim_audio_1978-06_62_6 (shell, hubs, slip sheets, guide rollers, pressure pad with spring-mounted felt). (5) Walter G. Salm, Cassette Tape Recorders: how they work, care and repair (1973), searched in full text at https://archive.org/details/cassettetapereco0000salm (the window that shows how much tape is left on each hub, two hubs, leader, flanged guide rollers, slip sheet liners, felt pressure pad on a spring, mu metal shield, shell halves, the two removable tabs). (6) Popular Mechanics Do-It-Yourself Encyclopedia, volume 5 (1986), searched in full text at https://archive.org/details/popularmechanics05cave (two shells, two hubs, slip-sheets, pressure-pad assemblies, metal shields). (7) A home computer maker's booklet, Getting the Most from Your Cassette System, searched in full text at https://archive.org/details/tibook_getting-the-most-from-your-cassette-system (breaking out the tabs to save a side, and covering the hole to record again). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's cassette, nothing traced. Licence: own work

How it works

A cassette tape is a small plastic shell with two hubs and a long magnetic tape inside. Look at the outside first, then open it and follow the tape from hub to hub.

Read the full guide

Two views, shut and open

Numbers 1 to 3 are on the closed cassette: the shell, the window, and the write-protect tabs on its top edge. Numbers 4 to 10 are inside: the hubs, the magnetic tape, the leader, the guide rollers, the pressure pad, the shield and the slip sheet.

The path of the tape

The tape leaves the full hub, turns around a guide roller and runs along the open bottom edge, where the head of the player meets it. The pressure pad holds it against the head. A second roller turns it up to the other hub.

To record on a side whose tab is broken out, cover the hole with a piece of sticky tape.

Questions and answers

What is inside a cassette tape?

Two hubs with a long magnetic tape wound between them, a guide roller in each lower corner, a felt pressure pad on a spring, and a slip sheet on each side so the tape turns smoothly.

What are the tabs on top of a cassette for?

They are write-protect tabs, one for each side. Breaking a tab out stops a recorder from recording over that side. Covering the hole lets it record again.

What is the clear tape at the start of a cassette?

It is the leader: a tough, non-magnetic strip at each end of the tape, joining it to a hub. Nothing can be recorded on it.

Which parts of a cassette tape player touch the tape?

The head, which records and plays; the capstan, a turning shaft that draws the tape past the head at a steady speed; and the pinch roller, a rubber roller that holds the tape against the capstan.