A magnetic 2-pin charging cable for watches and trackers whose two charging contacts sit 4mm apart, centre to centre, with swappable magnets for watches with reversed polarity.
This cable fits one thing: a watch or tracker with two flat charging contacts whose centres sit 4mm apart. The magnets pull the two probes onto those contacts, and the charge starts. Get the spacing right and it works like the original; get it wrong and nothing happens.
Measuring takes a minute and saves a return:
Compare the result with the common 2-pin sizes:
| Centre-to-centre gap | Cable to look for |
|---|---|
| About 2.5mm | 2-pin 2.5mm cable |
| About 2.8mm | FitCloudPro 2.8mm cable |
| About 2.84mm | 2-pin 2.84mm cable |
| 3.8–4.2mm | This 4mm cable |
| About 7.62mm | 2-pin 7.62mm cable |
The quickest shortcut is the original cable, if you still have it. Measure the gap between its two probes the same way; the spacing on the cable matches the spacing on the watch.
A watch whose original cable ends in a clip or cradle, or a band with a USB plug built into the strap, needs a different charger. For all the types, see the charger guide.
| Spec | Value |
|---|---|
| Model | Aliwisdom 2P-4mm |
| Pins | 2 |
| Pin pitch | 4mm centre to centre |
| Fits contact spacing | 3.8–4.2mm (4mm ±0.2mm) |
| Connection | Magnetic, upgraded pure-copper probes |
| Plug | USB-A on every version |
| Output | 5V DC, 1A, 5W |
| Full charge | About 2 hours |
| Protection | Over-voltage and over-current; short-circuit protection on some versions |
| Housing | PC + ABS |
| Cable | Flexible PVC, 5000+ bend tested |
| Cable length | 60cm (2-pack versions) |
| Weight | About 10 g per cable |
| Polarity | Removable magnets, swap to reverse |
| Works with | Smart watches, fitness trackers, bone-conduction headphones, smart glasses |
| Pack | 1 cable or 2 cables |
Once it fits, the cable becomes part of the weekly routine. Connect the USB plug to a computer, battery pack or mains adapter, bring the probes near the watch and the magnets snap into place. A full charge takes about 2 hours.
The cable outputs 5V at 1A, the standard USB level for wearables. Any phone charger or computer port can drive it; there is no need for a fast-charging brick, and the watch takes only what it needs.
Safety features cover the basics. Over-voltage and over-current protection guard the watch during charging, and some 2-pack versions add short-circuit protection. The housing is PC and ABS plastic, and the flexible PVC cable is bend tested more than 5,000 times.
| Power source | Good for |
|---|---|
| Laptop USB port | Desk-day top-ups |
| Wall adapter | The weekly full charge |
| Power bank | Hikes and trips |
Before each charge, run a dry cloth over the watch contacts. Skin oils and sweat build up on the metal after workouts and weaken the connection. A cotton bud with a little rubbing alcohol clears stubborn grime, as long as the watch dries fully before charging.
A spare cable also helps a streak. A watch that dies on a trip misses nights of sleep data and days of steps, which a 10-gram cable in the bag prevents.
Sometimes the spacing is right but the watch shows no charging icon. The usual cause is polarity. Some watches put the positive and negative contacts the opposite way round, and the cable's probes then meet the wrong contact.
The cable is built for this. Its two magnets can be removed and swapped, which flips how the cable seats on the watch.
If it still does not charge, run through the other common causes:
The magnetic hold is strong, and auto-alignment keeps the probes on the contacts even if the cable is nudged. It is still best to charge the watch on a flat surface where it will not be knocked off.
When the watch will not charge on any cable, the watch itself is the likely culprit. The not-turning-on guide works through that in order.
Charge in a cool spot, away from direct sun on a windowsill or a hot car dashboard. Heat is hard on small lithium batteries, and a warm watch on a warm cable ages faster than one charged on a desk.
Keep the removed magnets somewhere safe while you work. They are small and strong, and they will jump to the nearest steel surface if dropped.
The same 4mm magnetic head comes in several packs. The differences are the number of cables and their length; every version ends in a USB-A plug, which decides where you can charge.
| Version | Plug | Best for |
|---|---|---|
| 1 cable | USB-A | A straight replacement for a lost cable |
| 1 cable, Chnfut | USB-A | A spare for the desk drawer |
| 2-pack, 60cm | USB-A | One at home, one in the bag |
| 2-pack, Vtyzcm | USB-A | Home and work, or bed and bag |
A 2-pack makes sense for most owners. One cable lives by the bed or desk, the other travels, and a lost cable no longer means a dead watch. The single cable suits anyone who only needs to replace what went missing.
Check the ports you use most against the USB-A plug:
Cable length is easy to overlook. The 60cm cables in two of the USB-A 2-packs reach from a wall socket to a bedside table without the watch dangling, while a shorter lead suits a laptop or power bank in a bag.
Beyond watches, the cable fits other wearables with the same 4mm 2-pin contacts, such as some fitness trackers, bone-conduction headphones and smart glasses. The rule is the same for all of them: measure first.
Another 4mm option is the GloryFit magnetic cable 2-pack, also with USB-A plugs. Spare straps sit in the bands guide, and together they make a small kit that keeps your daily tracking going.
Measure centre to centre across the pair of contacts on the back. If it is between 3.8mm and 4.2mm, the cable fits.
The polarity may be reversed. Remove the two magnets from the charging head, swap them, and try again. Clean the contacts too.
About 2 hours for a typical watch, from a 5V USB source.
Yes. It draws standard 5V USB power from a wall adapter, laptop, car port or power bank.
One cable or a 2-pack, all with a USB-A plug; cable length varies. The 4mm magnetic head is the same.
