Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: What is the difference between the models HC-V520, HC-V520M and HC-V520K?
Document: My kids are in band and marching band, and last year I purchased the Panasonic HC-V10. I love the long zoom. It says "HD", but it's not (it's more like 480). I wanted to get an upgrade this year and decided on the V520 (80x) instead of the new V201 (only 38x). I still wanted the extra zoom. I need to purchase at least a 32GB card because of the larger files.
This is a small sacrifice considering most cameras don't come even close to the long range and I can get shots otherwise impossible.One more point - it shoots 1080P but in tests I could not discern any difference between that and the highest 1080i so save your chip and battery on that one.
But for me, long distance, stabilized, high def video is what I wanted. I upload to Youtube and share with the family and friends. It's perfect for what I need. As an added bonus, the stills are great. The V10 photos were .5 megapx (point five!) while the V520 is optical zoom and stabilized at 10 megapx. That makes for very useable long-range pics.
Once you are over the steep entry-level learning curve, you'll feel you are well on your way to becoming a pro.Is the video this camera produces better than what you can do on a smart phone? The two things that make a difference is its telephoto lens and its internal stabilizer. This not to say that you should use your smart phone for everything, but if you do, that is what you will be losing.Now then, this video camera also takes stills.
Of course this will not matter for 99% of consumers but if it does matter then you want to get the HC-V720 which will allow you to add another lens or filter. The V720 also has a better image sensor according to the review websites.One other bad is the fact that right now there are no 3rd party batteries and the extended Panasonic one cost $125.00!
The part numbers are VW-VBT190 (which comes in the box) or VW-VBT380. I did a side by side test with the V10, and the V520 clarity at 80X is awesome! I am so excited to have this upgraded camera.To be very clear, I am sure there are better cameras in the 1X to 16X range. I wanted to be able to zoom in on someone's face from at least 100 yards away. This will do it without having to do digital zoom.
very good for the money and its very useful and handy and comfortable. good deal for money and happy with the shipping.
lightweight, compact, easy to handle. great video under a variety of lighting conditions. good versatility with use of optional tripods. for people with shaky hands the image stablizing feature gives you a nice steady, sharp picture.
i DIDN'T HAVE TIME TO USE THIS CAMCORDER BEFORE WE LEFT FOR MONTANA, BUT IT'S SO EASY TO LEARN ITS BASICS, I HAVEN'T TRIED TO DO THE USB PORTS OR ANY OF THE OTHER MORE INTRICATE WORKS YET. I AM VERY IMPRESSED WITH THE 80 POWER ZOOM. IT IS REMARKABLE, MY TWO DAUGHTERS WERE SO IMPRESSED, I COULD ZOOM IN ON AN ANIMAL STANDING ON A MOUNTAIN OVER A HALF MILE AWAY AND SEE IT BETTER THAN MOST BINOCULARS.
easy to use. video looks good
Answer: The HC-V520 and 520K are the same model.  The K designates the camcorder is black in color.  The 520M is a model that is not sold in the USA and has an internal memory.