Does anyone know how AquaPlumb actually works (or if it does)?

this interesting sensor, if works:

http://vegetronix.com/products/aquaplumb/

here's gets interesting - @ pictures. notice strange? @ wire - like?

if guessed "speaker wire" - correct...maybe? - see link:

https://www.reddit.com/r/irrigation/comments/2ak7p5/new_tank_monitoring_system_out_of_speaker_wire/

notice reddit user name, , how poster begins "our company..." - so, poster representative of company makes aquaplumb (i dare poster owner).

so - how 1 use piece of two-wire speaker cable measure -any- liquid's level?

this seems common question here on arduino forum - @ least once week asking how measure liquid using light, or ultrasound, or other method. - here's method - seemingly proprietary; don't know if protected patent or whatnot - reverse engineered?

look @ pictures again - notice else cable? of dark-ish "lines" (or something) down center of length of cable - spaced evenly...?

according site, liquid never touches wires - wires won't corrode (the end supposedly sealed, , mention in faq can cut cable shorter, , re-calibrate - need re-seal end). supposedly works on type of liquid (even olive oil) - doesn't appear measuring resistance or anything. however, can't use in flammable liquids...

anyone have ideas? marks? kind of rf system? have difference in speaker cable wire (the "silver" wire vs. "copper" wire - 1 aluminum , other copper - i'm not sure speaker cable made of)?

i noticed has kind of special "sensor box" hook cable to, outputs changing voltage system, suppose. i'm curious whole thing, , wanted stir pot bit seeking liquid level detection solution well, , perhaps people thinking how device works.

could using capacitive sensing - project?

http://www.instructables.com/id/capacitive-fluid-level-sensor/?allsteps

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