(Left) Marui airsoft bullet box. (Middle) VsTank Pro airsoft bullet box. (Right) Hen Long airsoft bullet box.

It seems that Hen Long has more airsoft bullets than both combined judging at the box size. Let's go with a comparison of how the actual bullets look, starting with VsTank Pro's first. (Left) The airsoft bullet box contains the bullets shown aside. (Right) A close up picture of VsTank Pro's airsoft bullets.

These are the 6mm airsoft bullets which you want to use for your airsoft tank or airsoft gun. Note that the bullets aren't scratched or have any bad edges around the them, and they aren't broken.

How about Marui?
(Left) The airsoft bullet box contains the bullets shown aside. (Right) A close up picture of Marui's airsoft bullets.

They have a slightly different color but they have a good quality airsoft bullet as well, given that they are one of the big names when it comes to airsoft guns. They obviously know how to make airsoft bullets just like one would expect.

Now it comes to Hen Long. (Left) The airsoft bullet box contains the bullets shown aside. (Right) A close up picture of Hen Long's airsoft bullets.

You DON'T want to use these for your airsoft tank, or gun, or whatever. These bullets are broken, torn and some had the bullet skin peeled off. Simply, it's made of poor plastic and craftsmanship. If your airsoft tank or gun fired one of these bullets it will scratch the aluminum barrel which will cause damage in the long term. Also, the trajectory would be rather poor as a result.