Work out what your house is stuck on first, then look at what to buy. Every one of them says which problem it is for, because if the diagnosis doesn't call for it, we won't sell it to you.
The PRO+ suits external sound and suara tarik (ST). The 3.0 suits internal sound. Which one fits your house is a question for the diagnosis, not the catalog.
Spraying works too, it just doesn't last. What matters is how long the smell stays in the house, so what we teach is pushing the aroma into a pail and letting a fan carry it around. Send us your house first, then buy.
Mold brings the smell with it. Planks that are not clean make it harder for your colony to grow. This one started in our own family: the founder's father's house, planks covered in mold. He asked everyone he knew, nobody had an answer, so he went and found an anti-mold product himself and got a factory to make a version built for swiftlet houses. The story is here.
These are not what we lead with, but after a diagnosis they are often exactly what is needed.
MD Koay on the basics of attracting swiftlets. Once an MPH Top 10 bestseller, carried by MPH, Popular and Kinokuniya.
Take your phone and film your way in from the entrance hole, talking as you go. Record the internal sound for a while, then switch to the external sound and record that too. Spend the money once you know what is actually wrong.