At one time, Ben Wa balls were all made out of a solid metal
or even glass
but nowadays they also come in silicone
or other types of plastic and various stone materials including jade and even rose quartz. As a general rule, the steel balls can be a little more difficult to hold inside once they’re inserted so they work best for more experienced users. On the other hand, plastic tends to be a very smooth material and also isn’t as heavy as the steel balls so it usually works best for beginners to use Ben Wa balls made out of plastic.