Sold as cut strip - May or may not include connectors (2 or 3-pin JST) if you get middle piece
Higher density LEDS means much higher power usage over a certain distance - 18 Watts max (~3.5 Amps @ 5V) per meter instead of 9.6 Watts max (~2 Amps @ 5V). The max rating is assuming all the LEDs are on full white, usually the actual current for colorful design is about 1/3 to 1/2 the max current. A good power supply such as our 5V 10A supply is key!
Third, just because you have all those pixels doesn't mean you have the RAM for it - the entire strip must be buffered in memory, and we've found many Arduino UNO projects only have about 1500 bytes of RAM available after all the extras are included - enough for about 500 LED pixels. If you want to drive the entire strip and have some other libraries included, use a Mega.
