I took a risk and won... The product literally saved me in subjects that couldn't be passed even with an application... I bought it as a last resort and it helped me a lot...
OVERALL: Pay attention to the box with the batteries because that's where the most work is done and you need to make sure everything is good with the wires, cables, etc. in order to have a smooth usage...
I used the small magnet, threw it in my ear, and moved my head until it made a strong sound and you could tell it found the eardrum... Using the microscope only like that, you will be able to hear well and clearly, and it requires caution in gentle movements of the head, as it can move and you won't hear anymore... The larger magnet personally didn't work for me, so I didn't use it... Generally, neither of the two is visible externally, and if it is, then you haven't placed it properly... Don't be afraid to put it inside as the magnet it has to remove them is strong and does its job perfectly... CAUTION with the cables in general because there are quite a few and maybe with a simple short one it shows, so be careful with the good camouflage... Personally, I didn't use the microphone as I was taking photos and everything was fine... Be careful in case of poor connection of the audio jack with the phone, you will have to play with the cable, cases, etc... From the cables it has, I connected both of them as you will see that the small red one needs to be inserted because without it, it didn't work for me... It takes 3 small batteries and lasts a long time... Give clear instructions to the person outside to speak loudly, slowly, and clearly because the sound is decent but not crystal clear, so adjust accordingly... Overall, for its price, I would easily prefer it unless you no longer have an audio jack, then look for the next one with Bluetooth, which is reliable and tested...