The heartfreezer amulet (active) is a heartfreezer amulet that has been worn. The amulet is unstackable. It has 100 charges.
There is a chance to receive 25 Heart of ice tokens from combat drops or skilling while the amulet is equipped. After receiving the tokens, the amulet will lose 25 charges and a message will be displayed which reads: Your heartfreezer amulet feels colder for a moment, and you collect 25 Heart of Ice tokens.
Once the amulet runs out of charges, it becomes Heartfreezer amulet (empty) and can be destroyed for 5 more Hearts of Ice. Doing so will give the message: You gain 5 Hearts of Ice as you destroy the amulet. A purely cosmetic version of the Heartfreezer amulet can be retrieved from Diango in Draynor Village after all the charges have been used up and/or it is destroyed.
If it activates while you have a full inventory, it'll show the message: "Your heartfreezer amulet feels colder for a moment, but you don't have the space for any Hearts of Ice tokens in your inventory." and will retain its charge.