USB C Coupler Female to Female Adapter (2 Pack) 40Gbps 240W Type-C Extender Extension Thunderbolt QC & Data Transfer for USB-C Devices

Female USBC to Female USBC adapter. I used it to extend Poly bluetooth dongle from my docking station to get it higher in my office to increase the range of my headset. Also used it to extend the power USBC power cord for my Poly Headset charger. So far no issue, I did check that there is a limit to how far you can extend USBC cables but no issues with a 2 meter cable for just power and signal. I tried attach two USBC cables in series but the dongle wouldn't work. Cheaper than trying to find a USBC female to USBC male cable.

Picked this coupler up to extend my USB-C to the back seat of my car. Phone charges at 45W through it without issue.

I haven't had it long, but for what it is (see below!), this product seems very good. The problem is it is tricky in a few ways. Read on.Bottom line, two points:First, USB-C can do video (and high speed data), but video and really high speed data is only designed to work for a 2-meter cable. If you use this adapter to build yourself a much longer 4-meter cable (or more!), expect poor results. And even if used just for power delivery, you might get lower currents on too-long cables.Second, because of how USB-C cables are wired, you have a 50-50 chance that when you plug together two cables you will plug them together in a way that doesn't connect from one end all the way to the other. If this happens, try unplugging one of the cables from the adapter (just one of the two), turn that plug over, and plug it back into the adapter.The second point is an annoyance, but the first point is a big problem! What's the point of making a long cable if it won't work? Good question.In my case (see picture) I have a little hub that can handle power, ethernet, video, SD cards, and two more old style USB connections. It is small and has a very short cable: I don't want it hanging from my computer. I like using my laptop on my lap, and that hub dangling there is annoying. So I use this adapter put the hub at other end of a longer cable. A 2-meter cable. Yes, I am over the 2-meter limit, but only a little bit. I haven't tried it yet with video, but so far it works well for ethernet and power.Given these two limitations, this product is of limited value to most people. I am quite glad I have it, but you might not have a need for it.Explaining the 50-50 thing:A USB-C cable has two complete sets of contacts inside the connector on each of cable, but it has only one set of wires that go to the the length of the cable, so at one end only one of the two sets of contacts is connected to the wires inside the cable. And at the far end of the cable that one set of wires again connect to just one of the two sets of contacts. On both ends of the cable the other set of contacts are effectively dummies, they go no where. (The computer--or other device you plug the cable into--has the responsibility to figure out which contacts go to the other end and use them.)So what happens when we use this adapter to plug together two cables? Each cable has two sets of contacts on each end, only uses one set, but the adapter doesn't know which is which, it just connects each of the contacts it sees through from one cable to the other, whether they are in use or not. When you plug two cables together you have a 50-50 chance that you are connecting a set of contacts that ARE in use by one cable to dummy contacts that are NOT in use by the other cable. (Bah!) Similarly, you have a 50-50 chance of connecting contacts that ARE in use by one cable to contacts that ARE in use by the other cable. (Yay!) If you use the adapter in the unlucky configuration, it is as if you never plugged the two cables together at all.

I bought these to extend the input of a usb c/hdmi adapter for use with a Steam deck, & also had the experience of the adapter not working for me right away. I am using Monoprice cables on all sides, & only one of the usb c cables I had on hand was compatible in the end - it may be that usb 3 is required, or just that Monoprice is quirky af. I did need to try flipping the ends around as well, but it now works without any issues at all once I finagled a connection, so far, so good anyway. Would recommend at this price.

Tried all three couplers with various USB-C cables, ports, and devices. Sometimes it has no connection so you need to flip them and even then it maxed out at 40 MB/s instead of the supposed 40 Gb/s. This tells me it only has the connectors inside of it for USB 2.0. Useless for me as I needed something to allow easy access to some high speed USB-C ports for some external SSDs. Bypassing these couplers my devices get a little over 400 MB/s.I did not measure/confirm power wattage capability.

Using this item with 10 ft usb c cables makes it useful for extensions, it’s awkward to use however as it sometimes needs to be adjusted to properly connect to power/transfer. The quality of the product is highly unsatisfactory, i don’t really like the rubber, nor the actual female ports themselves as they seem to not be well made either. Useful overall.

When I realized I didn’t have the right cable solution on hand, female to female USB-C was needed. These Cellularize adapters are sleek and simple in the best way. By the way, if this solution does not at first work, flip one cable’s orientation as it snaps into the adapter. Although both sides of USB-C look identical, two joined together won’t always work without the “flip trick.”

This adapters are so well made! Been using them for almost three years now. They look and work like brand new!