From Analog.Man: BART (Big ass Russian transistors): these are available in 2020, BIG fuzz sounds but excellent cleanup throughout the volume pot range on your guitar. Cuts through great, some edge and crunch to the sounds. Run the FUZZ knob down a bit and the BIAS up a bit for cleaner sounds like the white dot NKT275. These will use the slightly larger case as they are too big for the small case. This case allows any options (top jacks, on/off pot, top power jack). These are a little noisy (white noise/hiss).