Tub drain style strainer 
Two small strainer: 2 1/4" diameter x 1" high (6 x 2.5 cm) 
One medium strainer: 2 3/4" diameter x 1" high (7 x 2.5 cm) 
One Large strainer: 4 1/2" diameter x 1 1/2" high (11.5 x 3.5 cm)