Quick Answer
NSF/ANSI 177 is the standard for shower filtration systems and certifies free chlorine reduction under defined test conditions. It is specific to chlorine reduction — it does not certify softening, chloramine, or all contaminants. ZOOSHEN lists applicable certifications after validation.
Problem
Shoppers see 'NSF certified' on packaging without knowing which standard applies or what it actually certifies, leading to inflated expectations.
Product Recommendation
ZOOSHEN will list applicable certifications (such as NSF/ANSI 177) for each product after final validation. We do not publish certification claims before they are verified.