Here's a short extract from our user manual - the Product guide which every box with the device is supplied with.
You can always buy a new evaCHILL cartridge on our website.
If you're not sure how to remove or replace the cartridge (which is also often referred as a "filter" online) from the device, please watch the video or read the instructions below.
Step by step: 
1. Disconnect the device from a power source.
2. Slide the handle backward.
3. Remove the cover and take out the funnel.
4. Take out the old cartridge by moving it upwards.
5. Place a new cartridge in place of the old one; it should fit easily as the new cartridge will have not yet expanded from previous uses. Check the orientation and keep pushing until the cartridge is in the center of the device.
6. Place the upper cover of the body back so that it fits in the slots. Slide the handle back to its original position.
7. The device is ready to use.
Important:
— Depending on usage and storage, the cartridge can last 3-6 months.
— Poor water quality reduces the lifespan of the cartridge.
— When replacing the cartridge do not remove any parts other than those described in this guide.
If you have more questions, please feel free to ask anything via our Contact form, we'll be glad to help you!