If you need to use multiple mics or 2 stereo pairs in front of one source, especially something like a choir, orchestra, big band or chamber or jazz ensemble, this is a great tool. You can easily set up various useful stereo mic configurations, like ORTF, A-B or X-Y. I use ORTF or X-Y on the centre pair of mic mounts and the outer pair extends for 40 or 60cm A-B using omni microphones. All mounts have a spacer, so you can offset any of them for height which is useful for X-Y where one mic must be higher than the other. It has angle and distance markings for the mic mounts, and a swivel joint where it connects to a mic stand with angle markings.
It is solidly constructed all in metal and seems very strong and durable. My only concern is that the assembly seems slightly inaccurate; the angle scale for the centre mount is off by a couple of degrees when read from either side, and the tightening rings for the mic clips on the mic mounts have jammed on the bottom of the threads. However, it was easy enough to dismantle the mounts and release the stuck threads.
There are equivalent mounts by other brands at unreasonably high prices, the t-bone unit seems like the only one at a fair and realistic price. Many t.bone products seem like this, all have been good (but not perfect) quality and excellent value for money at an affordable price.
I'm glad I bought this, it opens up some great possibilities for my mic setups without spending a ridiculous amount of money. The hardware can be just as important for getting the setup you need but it also needs to be economically viable. Until I found this unit I didn't know of anything at the right price, and it is a real asset to me for some recording jobs.