Based on the legendary green box, Valeton Tube Engine is low to medium gain overdrive with Bass and Treble knob. The enclosure is steel and the pedal feels solid also it’s very pedalboard friendly. Powered by 9V and no battery access.
It’s a good screamer type sound with a bit of hair and EQ flexibility. The output is moderate and have more gain than the screamer. Valeton Tube Engine truly shine with the Bass and Treble knob although the Bass knob can be very boomy. The Treble knob is pretty nice, not so much ice picking. It’s very warm overdrive pedal, works great with single coil. If you’re using humbucker just make sure not to dial too much Bass.
Pro : Small sized, very cheap, sounds good for the price point.
Con : No battery access.