Quick Answer
Check four things before buying a shower filter: (1) your shower connection (standard 1/2-inch fits most), (2) the media matches your water (chlorine vs chloramine), (3) the form factor fits your shower, and (4) the replacement cartridge cost over a year.
Problem
Shower filter listings are full of jargon and inflated stage counts. Buyers need a simple checklist to cut through the noise.
Product Recommendation
ZOOSHEN publishes connection, media, and cartridge details for each system, with validated specs after final testing. Start with the finder to narrow the range.