Component identification

[MK14]

So some kind of bridge resistor configuration.

[ArthurDent]

It appears that all 4 components in the modules are film resistors with the green resistors being lower value than the white ones. I suspect that these devices are balanced audio attenuators, or networks, with the green resistors being the input and output termination resistors and the white resistors being the series resistors between the input and output.  This would mean 1 & 3 are the input and 2 & 4 are the output, or visa-versa. I’ve provided a link to a reference and if you scan down you will find a drawing of an “O” attenuator and a description further down.

http://www.uneeda-audio.com/pads/

A guess without being able to personally check out the 4 variations of these modules is that the 3.5, 4.5, and 14 might be attenuation values and the 600 on all 4 versions could mean they are for 600 ohm audio circuits. If the resistance between 1 & 2 and 3 & 4 are higher for the units marked ‘14’ than for the ‘3.5’ and ‘4.5’, that would make sense for them being attenuators. It would also make sense that the numbering sequence is 1,2,4,3. Again, without actually being able to check them out, this is just a guess.