A late 19th century uterine dilator invented by Sims. As these instruments could cause cervical damage and bleeding they found less favour than the use of graduated bougies.
The instrument is cleverly engineered. Pressure applied to the two bladed handle causes the three blades of this uterine dilator to expand evenly. Once the required aperture had been obtained the position can be fixed by means of a screw.
Simms was most famous for the invention of his vaginal speculum. Despite being a pioneer of gynaecological research his use of female slaves has been questioned even in in the context of the mid 1900s.