Mariner Hanger Unit Housing - 205 Series, Stainless Steel 5.7/16" What does the 5M in

What does the 5M in 2350-5M-09 mean

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Mariner Hanger Unit Housing - 205 Series, Stainless Steel 5.7/16" What does the 5M inThe Mariner SHAM205 is an all stainless steel hanger unit housing manufactured from AISI 304 stainless steel using investment casting for a smooth finish that resists corrosion and simplifies washdown procedures. Machined for end cap compatibility. Designed to accept all Mariner 205 series bearing inserts. Specifications Housing Style Hanger Unit Series 205 Seal Type Silicone Seal with Flinger Material 304 Stainless Steel (Housing), 440C Stainless