From the manufacturer (via Google Translate from Russian):
Fortress is inspired by the philosophy of Bastl Kastle and Korg Volca Modular synthesizers. It consists of 4 separate modules (or blocks) that can be connected to each other with wires in any way you like, creating both classic and unusual combinations. Be imaginative and feel the flexibility of modular synthesis - every knob is modulated!
The main block of Fortress - the oscillator - has 8 Lo-Fi synthesis engines: Wavefold, Sync, Additive-1, Additive-2, FM, Formant, S&H and Noise. There is also a square wave sub-oscillator to add some fat!
The second important block of Fortress is the processor. It takes the signal as input and processes it, and can act as a filter, volume control, attenuator, additional VCO or LFO, and the cherry on the cake - it can even be a drum machine!
The final two blocks of the Fortress are two syncable LFOs. Both have an analog output with adjustable waveform, a meander (“square” or digital) output, and a Sample & Hold output that generates 8- or 16-note sequences. The former is also switchable to either an AR or AHR envelope generator, while the latter has a selectable frequency division when syncing.
The most interesting thing about any synthesizer is its back panel! Fortress has one mono audio output with a built-in 6-channel summer, a MIDI input (both TRS MIDI A/B and USB) with modulation, synchronization and the ability to play notes from an external sequencer, as well as an additional analog input/output for switching with other synthesizers.
Fortress is slightly larger than the palm of an adult’s hand and has a built-in battery for 8 hours of operation - experiment on the go! Included in the kit we supply a carrying case, patch cables and detailed instructions that will help even a beginner understand the difficult but wonderful world of modular synthesizers.
Spotted this on YouTube. Looks like the only distribution is a Russian webstore currently, I don’t see shipping options worldwide. Would love if someone else has info on whether this will see wider distribution. Presumably all digital - but looks quite interesting and fun. Price was listed at about 18000 rubles (around $225 USD currently).
Edit: just wanted to say although I think it’s a bit cheeky calling it Fortress, they do explicitly say it’s inspired by the Kastle, and it doesn’t appear to be a Behringer-esque clone of it, but instead seems to take that design idea in a few different directions. Also I don’t know anything about SxLab, just throwing this out there.