crossway is dual channel manual crossfader with clever normalization in 4hp.
left and right channels are swapped so you have L/R and R/L crossfading.
of course you can use the individual inputs too.
channel 1L is normalled to a dc offset voltage, so you can also send out a cv while fading easily.
(patch ideas in User Manual)
built: 50€
kit: 30€
pcbs+panel: 8€
no problemo modules 
