Good hardweare are things like wetdry filters and sumps for filtration. A nano tank that some people recommend is a Nano Cube. It is 12 gallons and has a wet/dry filter built into the back, it also has adequite lighting for some corals ans most nano tanks are home to just corals. Nano tanks can be hard to keep and you really must be up to the task and able to pay for the equipment and inhabitants most people would tell you to buy a tank that is 55+ gallons since these are easier to take care of.
HTH