this amplifier be well make , durable and meet all of the requirement for professional use . it be be widely use in the cable industry -lrb- contrary to some of the review here -rrb- . there be several company that make these and they all meet the frequency requirement -lrb- 5-1000 mhz -rrb- for modern hfc cable system . it be provide and install by cable guy and it cost $ 40 - $ 50 on average . First of all this device should only be use for you tv service . do not amplify the modem line . you need to use the splitter to split one line to the modem and the other should feed the amplifier and the rest of you outlet . this amplifier will increase you modem upstream return level . read the print on the amplifier : rtn -lrb- return -rrb- -8 dbmv . you upstream power level will increase and you modem will have to work harder to communicate out . also it will sometimes decrease you upstream signal-to-noise ratio -lrb- snr -rrb- . the amplifier be not a do-it-all miracle device that will solve all of you problem . it simply amplify the incoming signal . it do not filter the noise . this mean you incoming signal need to be clean and at acceptable level before the amplifier . so if you have 4 or more tv -lrb- on average , but this may vary -rrb- you will most likely benefit from this purchase . if you have more than that you should buy the single port version -lrb- cheaper -rrb- and use a 8 way splitter . in fact if you buy a single port version and use a 4 way splitter you will get the same signal level . however if you have problem I strongly recommend call you local cable co and get a tech out . if you be a diy person , make sure you do some research first and use quality equipment -lrb- like this amplifier -rrb- , rg6 60 % braid shield or better cable -lrb- quad shield be better -rrb- , compression fitting -lrb- like PPC , Thomas & Betts -rrb- and not crimp fitting -lrb- do not apply pressure on the coax -rrb- , splitter that do not have glue on the back cover and be rate 5-1000 mhz . by invest more money and get quality equipment it will help you have trouble-free service and will most likely save you some money in the long run . PS if you can get a power inserter -lrb- it look like a regular splitter but it be not -rrb- you can use it to back feed the power on one line so you do not need to have a power outlet right next to the amplifier -lrb- make sure you connect it to the `` remote power '' -lrb- sometimes `` DC IN\/RF OUT '' -rrb- port on the amplifier -rrb- .