B2 is a DIY-friendly analog synthesizer module in Eurorack format. It contains everything you need to create deep, thumping kick drums or cutting bass lines in one compact 14HP unit: A 1 V/Oct VCO with 4 waveforms, a 3-way waveform mixer with sub-octave sine wave, 2 fast, switchable AR/AD envelope generators, a high quality VCA, and a multi-mode VCF for additional tone shaping! 

New features of B2 from B1:

+ New reset/trigger circuit and faster minimum attack times (~25uS) without artifacts

+ Sub-octave sine

+ Wave select saw or 2x saw

+ New VCF with LP/BP/HP selection

+ Stable voltage references for VCO stability under power supply fluctuations

+ All OTAs are LM13700 for easy parts sourcing

More info here : https://westonaudio.com/index.html