 Cyanophages generally have isometric hexagonal heads with diameters ranging from 55 to 90 nm.There is large morphological variation in this group, which suggests that they infect a variety of host species.At the point of attachment between the long tail and the head there is a base plate where short pins are attached, a contractile sheath, and an internal core, similar to other bacteriophages in the Myoviridae.