Modules from Swedish company Steffcorp. Sadly they have closed shop for the time being.
This one’s from the first series of Arp inspired modules. A 10hp ARP 2600 type ADSR/AR. No, the color scheme I settled for in the first time around wasn’t that great. Yes, I did change it to a more ARP-ish orange/black later on (as in the top image).
12hp ARP 2600 4012 filter.