The Voltset devices plug into an Android phone and offer multimeter-type functions. The Mini Voltset measures voltage and continuity. The Mega Voltset adds resistance measurements.
On the one hand, a lot of traditional features of multimeters are missing (e.g., current measurements, diode testing, etc.). However, Tom Wang, the creator of the Voltset devices, wants to take advantage of the Android-powered host device by including a bunch of tutorials and educational materials to use on electronics projects.
Hat tip to ML