This item has 8 charges, and can be used as Bonus Action to activate, using it as the Greater invisibility spell. 

While wearing the Cloak and have the Invisibility active you gain advantage on Dexterity (stealth) checks.

The Invisibility drops if you are hit by an attack, or if the wearer has made contact with enough water. Thus, losing a charge.

Once all charges have been used you must succeed on an INT check DC10 to roll a D6 for recharge, the roll you get is the amount of uses you recharge. If the check is failed, you may make another INT check DC10 after a short rest. Or after a long rest your able to roll a 1d6+2 to regain charges.

The Cloak, also known as the Invisibility System, Chameleon Field or Shiftsuit, is an advanced piece of Yautja technology that is able to render the user invisible, or nearly invisible, to the naked eye, as well as many forms of electronic scanning. The Cloak warps light around the user's body in such a fashion that surfaces behind the creature are visible through the Predator's body. The effect is not perfect, often leaving a visible silhouette similar to heat haze, but in certain environments (and when the Predator remains motionless) it can effectively help a Predator to hide in plain sight.

Notes: Advantage: Stealth