Excerpt: When it comes to maintaining our Boneco P400 air purifier, we’ve always sought reliable replacements. The A401 A402 A403 HEPA Filter and Activated Carbon Filter for the Composite Filter (375×280×42mm) has been a go-to option, and we’re glad to share our experience. This three-in-one filter combines HEPA technology with activated carbon, effectively capturing particles, odors, and impurities for fresher air. The sizing is precise, ensuring a snug fit for our purifier. While compatibility is key, we recommend cross-checking our purifier model before purchasing. Overall, this replacement filter offers a practical and affordable solution for Boneco owners. Its dual-stage filtration system impressed us, balancing performance and longevity. For us, it’s a dependable choice in our ongoing quest for cleaner air at home.