I bought this amplifier as part of an upgrade to the original radio in my 24' fiberglass boat. I wasn't looking for a high end audio upgrade with massive sound, sub-woofers and wake tower speakers, I was just looking for decent quality sound and something noticeably better than stock. This is a compact, no-frills amp that will roughly double the volume output of a standard head unit at a very affordable price.I matched it with the new JVC KD-X35MBS head unit that provides all the FM/Bluetooth/Sirius sources I wanted and has all the equalizer controls, cross-over settings and balance/fade controls that I needed. (Note that this amp does not have any controls of its own, its just an amp. You will need to pair it with a head unit that gives you all the audio controls you need). I also used two pairs of Clarion 6.5" marine speakers mounted in the open part of the hull and in the enclosed cabin (i.e. set up as front and rear speakers).I am getting good punchy sound across the full range of frequencies with more than acceptable levels of bass (after a little tweaking of the equalizer controls on the head unit.). Volume is more than sufficient to cut through clearly with the engine and other ambient noise of a busy recreational lake.It is important to match this amp with speakers of the correct power handling. This amp will push out 100W max and 45W RMS. Its the RMS number you need to care about as this is the number that reflects the true continuous power capability without distorting. I matched with speakers rated at 100W max and 50W RMS which is ideal. If you match it with speakers of a lower RMS they will distort at higher volume levels. Conversely, if you match with speakers rated at a much higher RMS (say, more than 70) this little amp will likely not drive the voice coil in the speaker hard enough to develop the full sound the speaker is capable of.This amp is intended to be an affordable, good quality upgrade over stock radios and in that capacity it does a fantastic job. If you are looking for a high-end audio upgrade that is going "kick butt" this isn't the amp for you as it won't have the power or the features needed to support a high-end rig.I rated it only 4 stars because I am concerned about it failing due to heat. This little amp gets hot fast and the aluminum heat sink seems a little thin to fully dissipate the heat build up. Instructions say to install in a heat free location with good airflow and not in direct sunlight. Well, there is no such place on a fiberglass boat in the middle of summer! I installed mine in a bulkhead inside the enclosed cabin. The bulkhead has an opening to the outside under the dash for some airflow. That is about the coolest place on the boat that isn't directly exposed to water (this amp is not sealed - I would not recommend getting it wet!) but even so the cabin easily reaches 100 degrees or more, so we'll see what happens... If it makes it through the summer I'll upgrade to five stars.Ran it to a Kenwood or Pioneer head unit via RCA. Then upped the factory 5.25" to 6.5". Still fit in the factory last style Cherokee shrouds. Added foam below the mounts (metal speaker sides), and foam cones behind them too. System sounded absolutely awesome. Pair of Cerwin Vegas and another of Kenwoods. Just ran 12 gauge home spreaker wire to the new speakers, spliced in with the amp, although the amp wires seemed to be a much lower gauge. Regardless, worked perfectly and sounded awesome. Not a fan of speaker level inputs. Recommend RCA for any install, and never to run anything aftermarket off a factory head unit.For how large this little amp is, it puts out some decent power. We put an aftermarket radio and speakers in a 1997 Jeep, with a big amp powering a 12" sub in the back. The speakers always sounded quiet and would distort when we had the top off, especially when you cranked it up. The sub sounded great but the 22 watts RMS coming from the head unit was not enough for the speakers. We considered installing a larger amp but were seriously out of space. So I decided to try this little guy. So the install went smooth I was able to install it behind the radio on the right side kind of behind the passenger airbag. I used one screw to anchor it in place and then zip tied it to the airbag sensor bracket. It's in there good and tight and will not bounce around. Overall the sound is clean and clear and there was a noticeable difference in the volume. Overall it did the job. I don't think it's a true 45Watt per channel but my daughter is now happy and it seems to have filled out her sound system nicely. My only concern is the power wire. We have a 8 guage wire run all the way to the amp but the power wire on the amp itself is barely 14guage. I'm worried about that but overall no problems so far and she likes to blast it.4-26-2018 update. So far the amp as been rock solid. No problems at all.The only reason I'm giving 5 stars to this amplifier is because how small this amp is trust me this is really small plus the harness that comes with it has enough wire to connect to your speakers terminals that's a plus! You can mount this amp anywhere with no problem, power is ok but I was expecting some more power but considering the size of the amplifier I guess is ok, don't expect too much power out of this amplifier because you are not going to get it, I hook this up to two Rockford Fosgate 6.5 prime speakers and they sound great without the amp but sounds a little bit better with the amp, if you are looking for something not really loud, small and compact this is the way to go, if you are looking for power you better look for a different amp because for this same price you can find something powerful! But I'm ok with my purchase I just needed an amp for my door speakers I already have an amp for my subwoofers! I was trying to attache a picture of the amp to show you how small this is but for some reason the Amazon app doesn't allow me to do it but it just to give you an idea is the same size as my hand my hands are not big but not small either so you can have an idea on how small this is!After seeing the reveiws on this item and purchasing it for myself I had to give it a review. If you purchase this amp be sure you read the output on the description. It explains the item to a T. Don't look for a huge increase for what you are paying for. I told myself all I needed was about 5 more notches for my radio. Well this amp did just that. It won't give you a huge increase in sound but it will give you what you was lacking before you install it. For the price I am very happy with this amp. Although I have install many amps before. This amp is by far the easiest I ever install. Don't need to connect to the battery and no humming through the speakers. And so small you can place it anywhere and it want be in the way. I should have video the hold thing it was so fast to install. My 2016 Harley-Davidson Road Glide just smiles from aproval HAHAHAHAHA! If you need just a little more sound this is the item for you.The amplifier arriving time .I installed. I realise it’s killing the battery ! I connect yellow (+) and black(-) only and the amp it’s working ,not supposed to ! The remote cable (blue) doesn’t work..My husband bought this amplifier after changing the 4 speakers in his car. The puny 100-Watt amp standard in our Nissan Leaf wasn't powerful enough for the new speakers but this one is. He just loves the sound. Really great product.Shipped in no time!Great product thank youPeteBien mais je m'attendais a plus