Great price, great bit of gear! Works perfectly well for my set up.
I bought two of these as they are at a great price, and because my gear is all hardware with a fairly complex setup, and I found in multiple instances that even if a device (synth, MIDI controller etc) has MIDI IN and OUT ports, doesn't mean they both work simultaneously (I can't understand why) and obviously doesn't mean they can do MIDI thru or merge.
Also I don't need to have extremely strong build quality since they won't be moved from the desk.
So I'll outline my setup in case anyone with similar equipment is looking to know if these Miditech boxes will work ok. I suspect they will!
It's hard to put into understandable words (a picture would be better but I'll try anyway. You'd probably be as well drawing your own picture as you read down through this!)
I have Roland TR-8 Drum Machine with MIDI OUT port (master clock) going to Miditech box1 IN.
OUT1 on the Miditech box1 goes to a Korg Volca Beats IN port (for clock only, no need for MIDI controller control on the Beats) and OUT2 goes to IN on an Arturia KeyStep Arp/Sequencer. (There will be more devices added to the OUT3 and OUT4 at a later date. (Clearly, as you'll see from the rest of this, I'm completely addicted to hardware :)
So this keeps perfect clock time, no noticeable latency of any kind. No power issues with the Miditech box running off the TR-8.
Next, I have a Tascam FW1884 Mixer with inbuilt 4 IN / 4 OUT MIDI (2 IN > 4 OUT/THRU/MERGE simultaneously).
The KeyStep OUT port goes to FW1884 IN1 port (which passes clock to everything else).
A Korg Kontrol 49 MIDI controller OUT port goes to FW1884 IN2 port.
FW1884 OUT1, OUT2 and OUT3 ports go to a Volca Keys, a Novation Bass Station 2, and an Access Virus C Desktop ..for MIDI Controller control AND KeyStep arp/sequencing (and clock), on ALL of these synths.
FW1884 OUT4 port goes into second Miditech box IN port. Again, no noticeable latency or issues with power.
Miditech box2 OUT1 goes to the TR-8 IN (so some functions can be controlled by the MIDI controller such as scatter and sidechain).
Miditech box2 OUT2 goes to a Korg KP3, also so it can be controlled by the MIDI keyboard (ie: the hold button and effects volume).
Miditech box2 OUT3 goes to a Volca Bass.
Ok so all that's probably hard to follow but put as simply as possible, with all the gear tied together using two Miditech boxes, I can play and/or control a Volca Bass, Volca Beats, Access Virus C, Bass Station, TR-8, KP3 with the programmed K49 controller (specific synth determined by K49 scene and midi channel - just a 2 button press) AND I can play an arp or sequence with the KeyStep on any of the synths (excluding the Volca Beats) and switch between them very easily (again, specific synth determined by midi channel set on the KeyStep - also just a 2 button press). All latency free.
I am absolutely delighted with these Miditech boxes. No need for external power as they power off the MIDI IN device (although while I haven't had any issue myself, I believe some devices won't quite have enough power for it or won't pass the power through properly. This would not be the Miditech box at fault.)
I currently have no need for the filter on the Miditech boxes but tested it anyway and it worked very well. All switches off, everything gets through. One switch or more on, and the MIDI gets filtered accordingly.
Even if it didn't have the filter switches, they're still one of, if not THE cheapest 1 IN > 4 OUT/THRU MIDI boxes going. Not the strongest plastic shell I've ever seen but you should be fine if you don't get too rough with it.
Highly recommended!