discovery toys stack n pop

This toy has 5 foam rings that stack onto a white stick on a blue base. When the rings are pushed down, you can hear a click. Push the white button and the rings fly into the air. The toy was made by discovery toys company in the 1990's and discontinued. The age range starts at 18 months. I'm looking for the base especially, since it is so hard to find. The base must be in excellent working condition as I use it for infants and toddlers in my early intervention practice.