These Kärcher 6.904-143.0 filter bags, specifically the KFI 252 model, are designed to keep your vacuum cleaner running efficiently by capturing dust and debris. Each pack contains five bags made from two-ply paper, which provides a high level of tear resistance to prevent leaks during use while maintaining strong filtration performance. You can use these bags in a wide range of machines, including the WD 2 Premium and MV 2 Premium series, as well as various SE and NT models like the SE 3001 or NT 181 PROFI. They are also compatible with K-series vacuums such as the K 2501 and K 2601, making them a practical choice for anyone needing reliable replacements for their home or professional cleaning equipment.