Rosin dissolved in isopropyl alcohol with various activators. The recommended use according to the manufacturer is "SMD soldering," but it works excellently in general hand soldering applications.

Classified as ROL0, Rosin - Organic - Low activation - halogen-free (0), so it is not made to eat through heavy oxidation; in that case you want ROM1, ROH1, or anything that does not end in xxL0.

When opening the vial, the user gets hit in the face with the smell of isopropyl alcohol. The flux is liquid and sticky. Its residue is also sticky and hard. The manufacturer defines it as "no clean," which means that the flux will not create short circuits or eat away at the copper - silkscreen over time. It does NOT mean that it will look nice and clean; specifically, it leaves a brown sticky stain as I said above, which needs cleaning so it does not look bad and does not attract dust and dirt.

In terms of performance, it is quite predictable and does what it promises. One pass with the brush over the area is enough for it to work. But be careful with desoldering pumps, since it tends to make the plunger stick and need constant cleaning, which is common with all fluxes; I just mention it.

I have also used it as a booster on cheap solder wick and it worked without problems, since its liquid form allowed it to cover all the copper.

I really loved it! I built an entire keyboard with it and it was one of the cleanest jobs so far. No problems with soldering and super easy to clean afterwards. Although it says it leaves no residue at all, that's not true, it leaves a slight film, but with a microfiber cloth and a bit of isopropyl alcohol the PCB shines