STEM = Science, Technology, Engineering, Mathematics.
Depending on the supplier, STEM educational materials might include things like math manipulatives, DIY kits (for making clocks, radios, electronics etc.), anatomy models (skeletons, organs, etc.), collections (rocks, insect specimens, etc.), lab supplies, chemistry sets, microscopes, etc.
FUNique Science Materials and Toys
An online store offering a "fun and unique" (FUNique) selection of STEM materials and toys for learning about engineering, chemistry, mathematics, human body, entomology, astronomy, geology, history, and more.