In Vaishnava temple, we will get Theertham, Sadari and Thulasi after the prayer. After getting the Theertham, we bow down our head to get the Sadari. Sadari is said to be the form of Sri Nammalwar, who is also named as "Sadagopan". As Sri Nammalwar says in his Thiruvaaimozhi, that all our sins will vanish if we strongly attach ourselves to the divine feet.
In Sadari, we can find the thiruvadis (two feet at the top of the Sadari), which are said to be the feet of Sriman Narayanan and this says that Sri Nammalwar is holding the Thiruvadi of Sriman Narayanan on his head.
Sadari can be defined as geeridam with thirumal feet on that. Falling on feet is surrendering. By bowing and accepting sadari, we are falling and surrendering in the feet of lord thirumal.
Sadari are made in 22 gauge Brass or copper. Sadari are generallyavailable in 5”, 6”, 7” diameter measurements. Sadari height normally is .5” ~ 1” more than the diameter. Mostly sadari are silver or gold coated and used. We get sadari blessing in Perumal, Ramar, Vishnu, Anjaneyar temple etc.