NATIONAL FOREWORD

This Indian Standard (Part 20) which is identical to ISO 16610-20 : 2015 'Geometrical product specifications (GPS) - Filtration - Part 20: Linear profile filters - Basic concepts' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Engineering Metrology Sectional Committee and approval of the Production and General Engineering Division Council.