In short: a laptop chassis consists of four main parts, labelled A, B, C and D in the repair trade. A is the back cover of the display (the lid), B - the bezel around the screen, C - the palmrest, i.e. the upper part with the keyboard opening, and D - the bottom cover. Each of them comes in several versions within a single model, with different FRU numbers, and they are not always interchangeable.
This guide explains what is what, how Lenovo names these parts and which variants to watch out for, so you order a matching part the first time.
Part names follow Lenovo's service documentation (Hardware Maintenance Manual), and the variant examples are based on the FRU numbers of parts we hold in stock.
What do A, B, C and D cover mean?
The letter designations are shared across the whole repair industry. They start from the outside of a closed laptop:
| Letter | Common name | Names in Lenovo and supplier catalogues | What it is |
|---|---|---|---|
| A cover | Display lid, LCD cover | LCD rear cover, LCD back cover, top cover | The outer cover of the screen - the one with the logo, visible when the laptop is closed. |
| B cover | Display bezel | LCD bezel, bezel sheet | The frame around the display on the user side, with an opening for the camera. |
| C cover | Palmrest, upper case | Palmrest, keyboard bezel, upper case, top case | The top of the lower half: the hand rest area with openings for the keyboard and touchpad. |
| D cover | Bottom cover, base | Base cover, bottom cover, lower case | The underside of the laptop, usually with rubber feet and ventilation openings. |
On top of that come smaller chassis parts: hinges, the hinge cover (the trim between the screen and the base), port covers, rubber feet and screws. You will find them all in the other chassis parts category.
A naming trap. "Top cover" is used both for the display lid (A) and for the palmrest (C). To avoid confusion, describe the part by its letter or its function when ordering: "screen cover with the logo", "frame around the screen", "part with the keyboard opening", "bottom".
Display lid (A cover) - what variants exist?
This is our largest parts category and also the one where mistakes are easiest. For a single laptop model Lenovo can produce several lids that look almost identical from the outside. They differ in the mounts inside and in the openings.
1. Display type and resolution
Full HD, WQHD (2560x1440) and 4K panels differ in thickness and mounting, which is why lids are often tied to a specific panel. An example from our stock: for the ThinkPad P50 / P51 / P52 there are separate LCD covers for the 4K version (FRU 00UR812), the touch version (00UR811) and Full HD (01AV379, 01HY700).
2. Touch or non-touch screen
A touch panel has an additional digitizer layer and is thicker. The lid for the touch and non-touch versions is usually two different parts, e.g. for the ThinkPad X240 / X250 the non-touch LCD cover is FRU 04X5359.
3. RGB or IR camera
An IR camera (infrared, Windows Hello face login) has a different module and different openings than a standard RGB camera. You can recognise it by the extra windows next to the lens (IR LEDs) and by the face login option. Example: for the X1 Carbon 7th generation we have as many as seven different LCD covers, including FHD with an RGB camera, FHD with IR, WQHD with RGB, WQHD with IR and a touch version with IR.
4. Material and finish
The same model may be produced in different materials: carbon fibre (CFRP), plastic (e.g. PPS), aluminium, and on the X1 Carbon also a version with a visible fibre weave ("woven"). Example: the ThinkPad X13 Gen 2/3 has a carbon-fibre lid (CFRP, FRU 5CB0Z69296) and a plastic one (PPS, 5CB0Z69299). The ThinkPad E14 comes with a plastic or an aluminium lid, in black or silver.
5. Antennas and the WWAN version
In many laptops the WiFi antennas (and in modem versions also the LTE/5G antennas) run inside the display lid. Some covers are sold with antennas and some without, and WWAN and WLAN versions have different numbers - e.g. ThinkPad X390 Yoga: WWAN 01YU983, WLAN 01YU986.
6. With or without hinges
In some models, especially Legion laptops and thin designs, the lid is sold as an assembly together with the hinges (named "LCD cover with hinges"). When ordering, check whether you also need hinges or will transfer the old ones.
Display bezel (B cover) - what to watch out for?
- Camera opening: bezels for RGB and IR cameras have different openings - this is the most common variant in our stock. In newer ThinkPads the sliding camera cover (ThinkShutter) is a separate small part.
- Display type: a bezel for a 4K or touch panel may differ from the Full HD bezel (e.g. P50 4K UHD, FRU 00UR815).
- Plastic or adhesive bezel: in older ThinkPads the bezel is plastic and held by clips. In thinner designs it is a thin, adhesive bezel (e.g. the "bezel sheet" in the Legion 5 15 IRX10). An adhesive bezel usually cannot be stuck back on after removal - when replacing the display, have a new bezel and new mounting tapes ready.
- Inner and outer bezel: some models (e.g. T480s, X1 Carbon) have two layers - do not mix them up when ordering.
Palmrest (C cover) and bottom cover (D cover)
The palmrest has its own variants: with or without a fingerprint reader, with keyboard backlight, in a WWAN or WLAN version, with an opening for a SmartCard reader. In some models (especially IdeaPad and ThinkBook) the palmrest is sold together with the keyboard. This is described in detail in our guide ThinkPad palmrest and chassis - how to choose, and the difference between standard and island-style palmrests - in the guide on keyboard layouts.
The bottom cover most often differs in:
- WWAN version - a cut-out for the SIM card tray (a SIM slot in the bottom = WWAN version),
- colour and material - e.g. the Legion 5 15 IAH7 in Storm Grey has a different number than the black version,
- contents - whether rubber feet and port covers are included.
How to order the right chassis part - step by step
- Read the machine type (MTM) from the label underneath the laptop - e.g. 20QD. The name "ThinkPad X1 Carbon" alone is not enough, as it covers more than a dozen generations.
- Determine which part you are replacing - A, B, C or D (table at the top of the page).
- Check the FRU number on the old part. The inside of chassis parts usually carries a label or an embossed number. This is the surest method - how to read it is described in our guide on the FRU number.
- For the lid and bezel, determine: display resolution (in Windows: Settings, Display), touch yes/no, RGB or IR camera (does face login work).
- For the palmrest and bottom cover, determine: SIM slot (WWAN), fingerprint reader, colour.
- Compare with the listing description or send us a photo of the label - we will confirm compatibility before shipping.
Frequently asked questions
What is a palmrest?
The palmrest (C cover) is the top of the lower half of the laptop - the surface you rest your hands on while typing. It has openings for the keyboard and touchpad, and on ThinkPads often also for the fingerprint reader and the TrackPoint buttons.
How does the LCD cover differ from the LCD bezel?
The LCD cover (A cover) is the outer cover of the screen with the logo. The bezel (B cover) is the frame around the screen visible from the user side. The display panel sits between them.
Does an LCD cover fit all versions of the same model?
Not always. Lids differ depending on display resolution, touch, camera type (RGB/IR), material, colour and antennas. For example, for the X1 Carbon 7th generation we have seven different LCD cover versions.
My chassis cracked by the hinge. What should I replace?
Most often the lid (A) or the bottom (D) cracks where the hinge is mounted. Before ordering a cover, check the hinges too - a hinge that has become too stiff is a common cause of cracks. Symptoms of worn hinges are described in our guide laptop hinges - diagnostics.
How do I know whether I have an IR camera?
An IR camera lets you log in with your face (Windows Hello). Next to the lens you can see extra windows with infrared LEDs. More about camera types in our guide webcams in Lenovo laptops.
Looking for Lenovo chassis parts?
At ABCDEAL we have hundreds of LCD covers, LCD bezels, palmrests and bottom covers for ThinkPad, IdeaPad, ThinkBook, Yoga and Legion laptops - original Lenovo parts, new and pulled from devices.
Not sure which version to order? Send us the machine type from the label and a photo of the old part - we will match the right FRU number.
📞 +48 601 415 357 / +48 33 853 26 20 · ✉️ sklep@abcdeal.pl