Vaginal speculums usually have either three round prongs or two rounded ears. They usually also have a mechanism that can be used to keep the toy from closing.
Speculums are usually made of metal but plastic variants are becomming more and more common because of their lower price and safety - they are discarded after one time use.

Anal speculums are similar to vaginal ones but usually smaller. They can be used for anal dilation or gaping. Since the anus is much stronger than vaginal muscles, plastic speculums are not recommended for anal use - they can and will break under stress.