Airfrex Bluetooth Adapter and Wireless Audio Receiver with Microphone and 2.5mm Jack for Sennheiser HD598 / HD598Cs / HD598SE / HD595 / HD599 / HD559 / HD569 / HD579 / HD518 / HD558 Headphones

This actually ended up being more impressive than I expected. It can connect to multiple devices at once however u can only hear one device at a time but its still super convenient. The sound quality is also really unexpectedly good, i was so pleasantly surprised with how good the music sounded, and i have not used it long enough to say about the battery but so far it has been alright. I have no complains about it at all, only that i wish i has gotten it sooner cause i would have benefited from it so much.

Very easy to set up, audio is pretty good the only thing I'd say could improve is the battery life, seem to get 5 hours use before having to charge. Apart from that I would recommend it.

Sound quality and ease of use is excellent, would like a slightly longer range and battery life but very pleased with the purchase.

Worked well while it lasted but now the battery will no longer charge. You can plug it in, red light comes up indicating it's charging then goes off. If you leave it on when you go to use it it'll report 20% battery and then die within 3 minutes.

Delivery was later than promise but supplier kept me informed and not an issue for me. At first, I thought I had wrong model since different marking from photo and was only getting left ear sound. Again supplier support was good. I actually have Sennheisers that didn’t match their model numbers. However, with a “jiggle” of the device, it now works really well. The sound is great.Check the detail level of your headphone model number to ensure compatibility with the supplier’s statement.

Bought this for my Wired AKG's and it works great. Fantastic sound quality and more than enough volume. Fits the headphones well and is very unobtrusive. Very impressed and much cheaper than buying wireless headphones. Highly recommended product if this is the type of thing you are looking for.

I've been using this adapter for about a fortnight with my wired Sennheiser HD558's, and overall I'm fairly happy with it. Finally my favourite (open-backed) headphones can be wire-free!Pros: Good sound quality. Very small and light and plugs directly into the headphones meaning there's no trailing wires. Easy to set-up and use. No signal drop-outs provided there's a clear line of sight between the iphone and adapter.Cons: Battery life (at around 6 hours) is quite short. Bass boost causes a constant crackling noise so has to be switched off. When the iphone is in my trouser pocket, the signal cuts-out momentarily every 5 minutes or so - a problem I don't have with the various bluetooth headphones I own (Sennheiser PXC 550 and Jabra Move - both excellent headphones, BTW, but not open-backed). Range through walls isn't the best.Updated my rating from 3 to 4 stars having bought a second one so I can hot-swap between them as the battery runs out so always can have a charged airfrex. Have been using them for a few months now and happy with my purchases!

I have ordered this twice as the first time I ordered I received the wrong version, AIU5 instead of SEHD. Sent it back and ordered again and again got the AIU5 again. Confused.The AIU5 does at least have a 2.5mm jack so thats something.I have the Sennheiser 599s and thought eh, I'll try it. I paired to to my Samsung phone, turned on my music and it worked. Wanted to test the range so left my phone on my desk and walked downstairs, I live in a 3 floor house and desk is on the top floor and when I got to the ground floor the connection started going spotty so range seems good.I then paired it to my pc and played some music, that works nicely as does it when watching YouTube or movies and with a bit of work got it working with games, I had to quit the game, disconnect and then reconnect the headphones, select what I used as default when headphones are connected and was testing once in game I can both listen to music quietly and hear the game and the sound is still perfect through my 599s.I decided I'd keep the AIU5 as at least it works and I don't have to go through the returns hassle / order again/ hope its the right one this time/ oh... disappointment.Edit;I reached out to Airfrex and it turns out this is the right model it was a mistake with printing on the end of it but the AUI5 is the right one for my headphones. I wonder if they will fix this issue.Edit 20th May 2025...I've had this for almost 2 years and it has worked well, but now, it's become an agoraphobic adapter, doesn't like being outside.When outdoors the adapter gives off a constant beeping sound every 30 seconds, it's not the low battery beeping it's a 1 second single beep but happens consistently when using out and about, at home it doesn't do that and works normally. I am stumped at what could be causing this.Edit June 6th 2025. I brought a second one and this one now has a voice that tells you power on and off, connected and disconnect and low battery. It can be charged when in use now too. Will see how long this new one lasts.