This is a compressor from AMDEK, a self-made effector brand under Roland. AMDEK effectors are often made with reference to similar BOSS products of the same period, and this one also uses the same OTA (Operational Transconductance Amplifier) circuit as the CS-2, characterized by a clear compression effect. Furthermore, it has the same 2-knob design as the Dyna Comp, allowing for intuitive operation. Operation has been confirmed (with battery). Power supply is DC9V, with both external and 9V battery options. However, please note that the external power input is a 3.5mm mini-jack.