Suboscillator
This 1/3 height micro module creates 2 outputs of square waves, one and two octaves below the incoming signal. It also produces another output 2 octaves below the incoming signal with a Pulse wave. There is also a mix output where the levels of the additional sounds can be controlled and combined with the original signal.
https://www.tangiblewaves.com/store/p182/uSUBOCTAVE.html
This Module is currently available.
Half Height Module
$34