iPhone Model Number Explained: A-Number vs Part Number (MXXX LL/A)
iPhone model number explained: what the A-number and the part number (like MXXX LL/A) mean, how to read the first letter and region code, and spot refurbished units.
iSerial TeamUpdated · 7 min read
In this article
Open Settings on any iPhone and you’ll find two very different codes hiding behind one label. One looks like MTUW3LL/A; tap it and it turns into something like A3090. Most people never notice the switch — but for a buyer, a reseller or a repair shop, those two codes answer different questions: what hardware is this, and how, where and in what condition was it sold.
This guide breaks both codes apart character by character, explains why they exist, and shows how to use them to catch region swaps, refurbished units sold as new and boxes that don’t belong to the phone inside.
Two codes, two jobs
Apple uses the word “model” loosely, so it helps to separate the two identifiers clearly:
Part number (e.g. MTUW3LL/A) | A-number (e.g. A3090) | |
|---|---|---|
| Describes | One exact retail configuration: model, color, storage, sales channel and region | A hardware variant certified with regulators: radio bands, SIM layout, approvals |
| Who uses it | Retailers, distributors, carriers, Apple’s sales and service systems | Regulators (FCC and others), accessory makers, repair shops |
| How many per iPhone model | Dozens — one per color × storage × region × channel | A handful — usually one per group of markets |
| Where printed | Box label, Settings, Apple’s records | Settings, regulatory info, SIM tray slot (newer models) or back case (older models) |
In short: the A-number tells you which radio hardware is inside; the part number tells you which product Apple actually sold. The same A-number can sit behind fifty different part numbers.
How to find both on the phone
- Open Settings › General › About.
- Look at the line labeled Model Number. By default it shows the part number (a string ending in
/A). - Tap it once — it toggles to the A-number (a capital A followed by four digits). Tap again to switch back.
Other places to cross-check:
- SIM tray slot: on iPhone 8 and later, the A-number is printed inside the SIM slot (you need a light to see it). US models from iPhone 14 onward have no tray, because they’re eSIM-only.
- Back case: on older models (roughly iPhone 5 to iPhone 7), the A-number is printed in small text on the back.
- Box label: shows the part number, serial number and IMEI. It does not prove anything on its own — boxes are easy to swap.
- Settings › General › Legal & Regulatory: shows certification marks and often the A-number for the market.
Reading the part number, character by character
A typical modern part number has three pieces: a prefix letter, a configuration code and a region suffix. Take MTUW3LL/A:
M— the sales channel / condition prefix (explained below).TUW3— Apple’s internal code for this exact model, color and storage combination. It isn’t meant to be decoded by humans; it’s a catalog key. The same phone in a different color gets a different code.LL/A— the region (or market) the unit was built and packaged for.
Older part numbers were shorter (for example a five-character body before the region), but the logic is the same: first letter, config code, region.
The first letter: M, F, N or P
| Prefix | What it generally indicates | What it means for a buyer |
|---|---|---|
| M | Standard retail unit sold new | The normal case. Says nothing about how the phone was treated after sale. |
| F | Refurbished unit (Apple Certified Refurbished or a refurb program) | Fine if priced and described as refurbished. A red flag if sold as “brand new”. |
| N | Replacement unit issued through Apple service | The original phone was swapped under warranty or AppleCare. Not bad — but the warranty dates follow the original purchase. |
| P | Personalized order, such as an engraved device | Rare on iPhones today; more common on iPads and AirPods. |
Treat this as a strong indicator rather than a legal guarantee. The prefix is set when the unit is configured, so it reflects how Apple supplied the device — not whether a later third-party repair happened.
The region suffix: LL/A, B/A, ZP/A, CH/A and others
The letters before /A point to the market the unit was intended for. Some commonly seen examples:
LL/A— United StatesB/A— United Kingdom and IrelandZD/A— several continental European countriesZP/A— Hong Kong and MacauCH/A— mainland ChinaJ/A— JapanX/A— Australia and New ZealandHN/A— IndiaAE/A— UAE and parts of the Middle East
Apple doesn’t publish an official list, and codes are occasionally reused or reassigned between markets, so treat this as a guide. The region suffix tells you where a unit was meant to be sold; it doesn’t tell you whether the phone is carrier-locked — that’s a separate record.
Why region matters more than people think
Region isn’t just paperwork. Different markets get genuinely different hardware and software behavior:
- SIM layout: US models from iPhone 14 onward are eSIM-only. Mainland China, Hong Kong and Macau models have commonly offered dual physical nano-SIM. Most other markets ship one nano-SIM plus eSIM.
- Radio bands: different A-numbers support different 5G and LTE band combinations. A phone can work abroad but miss bands your local carrier relies on. See whether a US iPhone works abroad for the details.
- Camera shutter sound: units sold in Japan (and some other markets) play a shutter sound that can’t be muted, regardless of where you use them.
- Warranty handling: Apple’s limited warranty is generally honored internationally for iPhone, but some service options are country-specific. The purchase country check tells you where Apple recorded the sale.
Spotting refurbished, replaced or swapped phones
The real power of the part number shows up when you compare it with other sources. Here are the mismatches worth catching:
Settings says F, the box says M
A refurbished phone has been placed in a new-looking retail box. This is the classic “sealed, never used” scam. The phone may be perfectly good, but you’re paying a new-phone price for a refurb.
Settings says N
The unit is an Apple service replacement. Ask the seller for the story and check warranty dates; the replacement inherits the original unit’s coverage. Read what “replaced” and “replacement” mean in an IMEI report.
Region on the box doesn’t match Settings
Box says B/A, Settings says ZP/A? The box belongs to a different phone. Check that the IMEI and serial on the box match Settings too.
Part number doesn’t match the color or storage
The configuration code maps to one color and capacity. If Apple’s records say the part number is a 128 GB black unit and the phone in your hand shows 256 GB in a different color, something has been swapped — case, board or listing details.
To compare the phone against Apple’s own records rather than the seller’s word, run a part number / MPN check (works with IMEI or serial) or the iPhone-specific part number check. The All-in-one Basic Info report adds model, color and storage in one go, and the purchase date check shows whether a “new” phone has actually been on sale for years.
The A-number in practice
The A-number matters most in three situations:
- Buying parts: back glass, SIM trays and some flex cables differ between A-numbers of the same iPhone. A dual-SIM tray from a Hong Kong model won’t fit a single-SIM frame.
- Importing: if you’re buying a phone from another country, compare its A-number’s supported bands (listed on Apple’s technical specifications pages at support.apple.com) with your carrier’s network.
- Spotting fakes: clones often show an A-number that doesn’t exist for that model, or one that belongs to a different generation. Combine it with the serial — our serial decoder guide explains what older serials reveal — and the IMEI’s TAC.
You can decode an older 12-character Apple serial right here and see if its era matches the model you’re being offered:
A quick verification routine
- Settings › General › About: note the part number, then tap to note the A-number.
- Note the serial and IMEI on the same screen; dial
*#06#to confirm the IMEI. - Compare all three with the box label. Any mismatch means the box isn’t original to the phone.
- Check the prefix letter against the listing (“new”, “refurbished”, “open box”).
- Check the region against your needs: SIM layout, bands, shutter sound.
- Run a part number and basic info check to confirm Apple’s records agree with the phone.
For the full Apple verification process, see the is my iPhone original page.
Check the records
Enter the IMEI or serial to pull the part number, model and purchase details from Apple-sourced records:
Frequently asked questions
What does LL/A mean on an iPhone?
LL/A is the region suffix Apple uses for units built for the United States market. It tells you where the iPhone was intended to be sold, not whether it is carrier-locked.
How do I see the A-number on my iPhone?
Go to Settings › General › About and tap the Model Number line. It switches from the part number (ending in /A) to the A-number, such as A3090. Tap again to switch back.
What does an F at the start of the model number mean?
An F prefix generally indicates a refurbished unit. It is fine when the phone is sold as refurbished, but a warning sign if the seller describes it as brand new.
Does the model number show if an iPhone is unlocked?
No. The part number shows the intended region and sales channel, but carrier lock status is a separate record. Use a carrier and SIM-lock check to confirm it.
Is an iPhone with an N prefix bad to buy?
Not necessarily. N usually means Apple issued it as a service replacement. It carries the remaining coverage of the original device, so check the warranty and purchase date before you pay.
