According to the makers, each filter lasts 250-300 exhales. Which is great compared to others that usually only last 150-200. The price is also great at $10 a pop, so you can't beat that. It also comes packaged well, and their shipping is fast! Got a refill for my starter kit, as the starter kit comes with 1 filter & the rubber holder for your SLEAV and a JUUL (or similar device).
Great little device and can't wait to put it through it's paces in places where vaping requires more discretion.