Here you'll find a selection of Drain Plugs from Amar, Moeller/Scepter Marine and Sea-Dog. Types include snap handle, bung with housing, and automatic flapper. 

For drain plugs typically used in sailboat applications, see Drain Plugs in our Sailboat Hardware & Rigging category.
Scepter Marine Drain Tube - Formed Brass
Item # 16782
Sea-Dog Drain Tube - Formed Brass
Item # 709783
Sea-Dog Drain Plug for Avon Rib Inflatables - Nylon
Item # 710989