The Meng Qi Brass is a passive 1/8" Banana Jack format jumbler with DC blocking switch and optional negative voltage blocking.

The Meng Qi Brass is a simple 1/8" Banana Jack format jumbler. It includes 9 channels of connector conversion. Each channel has a switch for inserting a DC blocking capacitor. If the kit is built up with diodes you can set it up to block all negative voltage as well which is handy for interfacing with Ciat Lonbarde and Lorre Mill (double knot) gear. To remove this feature, simply leave out the diodes, and run solder/lead jumpers across where the resistors were supposed to be installed. The center Banana Jack is a ground jack for interfacing w/ external banana gear (this is required to ensure proper grounding between gear with isolated grounds) The kit is quick and easy to assemble. Great for beginners!

https://modularaddict.com/manufacturer/meng-qi/mengqi-brassx-kit