So have built 4 or 5 already, they seem to work well. For machines with built in BT the trick seems to be to unpair/forget all current BT devices, turn off bluetooth and then reboot. Next boot the USB stick becomes the default. Then pair a device or two with it and subsequent boots will always use the USB. For the naysayers who wonder why this will work while all of the other USB sticks fail...THERE IS AN ACTUAL APPLE BLUETOOTH CARD IN THE DONGLE !!! The other reason this works is that if you look in system profiler right now, I'll bet dollars to doughnuts that you will find that your current Mac BT is showing up under USB. So it isn't surprising for the OS at all to find BT there since that is where it usually shows up. We have rolled out a new website and have begun transitioning to selling there. Will allow lower prices. Will also allow taking money orders for those afraid of using CC online. Of the 5 pictured, the middle one is obviously the proof-of-concept and we won't be sending them out quite that....bare. But I have to admit that it takes me a couple hours to make one so I am going to admit defeat and import them from China pre-made for most orders. (Giant blue one from China) The others I made and they are certainly sleeker but with time constraints, life, etc I just can't toss that much time into them without charging $200 for them, and then nobody would want them. Since I already ordered parts for 40 or so I will be making a few here and there but bulk will be the Chinese version. What will this do for you? It will enable BT 4.0 LE which may or may not be useful. In the original Yosemite DP this was all you needed to enable some nifty features. They have since "Apple-ized" it and put in little tricks to allow 2012 or newer machines to use Handoff/Airdrop (with IOS 8) running same hardware as older machines that they WON'T allow it on. So slapping one of these in won't enable it all by itself. There are kext hacks by nicklad and another guy that SHOULD enable it on some machines, but we don't really know which ones until people start playing with these on various machines. So why bother? It will cut down the number of things that need to be hacked, pure and simple. It is likely that you could use a regular BT 4.0 adapter but you would definitely also need to do some kext hacks to make it appear to the system as an Apple part. So you would need to hack BT kexts AND hack WiFi kexts. if it doesn't work, will be hard to know what the problem is. All pieces in your mac have a variety of codes that identify them and determine which drivers they load. A given device can have at least 4. Device id, subsystem id, Vendor id, and subsystem vendor id. As you can imagine, if Belcom or OWC started making parts that used Apple's vendor and subvendor ids there would be a team of lawyers getting rich. The only way to sidestep this check is to use Apple's own parts. It is thus invisible as an "addition" and just reads as an intrinsic part of the machine. So, they will go up on the website next week. If there is someone in LA who enjoys hacking and is trying Yosemite on an older "unsupported" machine, pm me. If you would like to test one before next week and see if they can enable handoff/continuity with one of these and the already existent "hack" for the WiFi. In fact, someone can have the "proof-of-concept" version FOR FREE if they promise to do some hack testing. BTW, this photo was transferred from 5S to rMBP via Airdrop using BT.