The water saver trap primer utilizes the temporary "head" of water in the p-trap which occurs during use of certain plumbing fixtures like lavatories and drinking fountains. This temporary head of water is sufficient to cause an "overflow" through the connection to allow a small amount of water to flow by gravity through a pipe under the floor to the floor drain trap primer connection. Thus, the floor drain trap seal is maintained.
Smith® Prime-Eze Trap Primer, Water Saver, 1/2 in Pipe, 6 in Length, Ground Joint, For Use With: 2000 Series Floor Drains, Cast Bronze, Satin Chrome Plated