●Type 21 mechanical seals shaft size 1.125/1.25/1.375/1.5/1.625/1.875 inch. ●Replacement pump seal suitable for multistage pump, easy and convenient installation. ●Exquisite craftsmanship and optimized materials.Carbon/Ceramic/NBR ●Strong fastening to reduce noise. ●Mechanical seal is suitable for water treatment systems, cleaning systems, seawater systems, ultrafiltration systems, reverse osmosis systems, which can also be used in swimming pools, bathrooms, acid and alkali transport.