My cell phone's speaker is like most, not exactly the best in terms of volume and quality of sound. And considering the technical challenges of putting a speaker into a piece of electronics not more than 1/4" thick that sounds half-way decent is remarkable that they work at all. However, depending on your particular brand and model of phone the speaker's volume and quality of sound will vary. If you're in a situation where there's significant ambient noise your cell phone's speaker, as good as it may be, may not be adequate. Or perhaps you're a bit challenged with your hearing and need something to boost the sound. I needed a boost to my cell phone's sound when using WAZE (a free navigation app for Android and Apple phones). Ordinarily my cell phones volume is loud enough, especially with the speaker-phone on. But in one of my cars which is not especially sound proof, with traffic noise it was sometimes hard to fully hear what WAZE was saying and I wanted something that was wire-free to boost the sound. There are a number of options for this kind of issue. For example, you could use a Bluetooth speaker. However, you'd need to find one small enough to fit somewhere in the car and attach it firmly just in case of an accident because you don't want lose items to become dangerous projectiles. In addition, you'd have to power the speaker either with its own battery or using the cars power via the cigarettes' lighter perhaps - again, more wires. You could also you a Bluetooth set of earbuds if you don't mind having something stuck in your ears. Now if your phone has a headphone jack you could use a wired set of earbuds, but then you've got wires again. This is where the Leadsound Crystal speaker shines: As long as your phone has a headphone jack, just plug this circular wonder into the jack, turn it on, and you've just amplified the volume of your mobile phone by a factor of at least 5, and you've also improved on voice intelligibility as well. Some things to point out: As previously stated, the speaker requires a headphone jack on the cell phone. Most Android phones have headphone jacks, but most of the newer iPhones are not going to work because Apple took away headphone jacks on their newer phones - in this case look elsewhere because you'll need a Bluetooth solution. This speaker has its own lithium battery which means it needs to be charged. The advantage with having an internal battery is that the speaker is not a "passive device" that uses the battery on the cell phone which will drain it faster than usual, instead it has its own amplifier that runs off its internal battery which spares your cell phone's battery. The speaker comes with its own carry case. OPERATION: There are two modes: auto, which turns the speaker off if it does not get an audio signal from the cell phone after 5 minutes, or manual, which keeps the speaker on. If you're using WAZE there may be periods where there's no voice from WAZE for 5 minutes or more, in which case you don't want the speaker to turn off and miss what WAZE says next, so it's a good idea to keep the speaker always on (manual mode, always on). The speaker's volume is controlled by your cell phone's volume setting. The speaker comes with its own USB cable to charge with (it does not come with a charger) and can use the typical USB charger. For charging you can use a cigarette lighter to USB adapter for use in your car while driving in case you need to recharge the speaker. The speaker is 'out in the open' at the front and you can actually see it more and feel it while holding your phone. PROS: 1 - Big sound from a tiny speaker 2 - Built in battery to power its own amplifier and speaker 3 - Does not use the battery power from the cell phone 4 - Significantly improves volume and intelligibility 5 - Carry case for speaker 6 - USB charger cord included 7 - Very simple to use CONS: 1 - Requires your cell phone to have a headphone jack. 2 - The off/on switch is at the back and you press it inward to turn the device Off or On (read instructions) - So be careful you don't press the front of the speaker in, thinking it is the off/on switch, and damaging it. If your phone has a headphone jack and you don't want to run wires or use a Bluetooth option, this is a really worthwhile and very inexpensive way to boost the volume - and intelligibility - of your phones sound. And yes, I would recommend it to a friend !