THERE ARE SEVERAL OF THESE KINDS OF PRODUCTS ON THE MARKET

THEY ALL WORK FINE, THEY'RE ALL A BIT OVERPRICED FOR WHAT THEY ARE (A POT WITH A SILICONE BASED THERMOCOUPLE GLUED TO THE BOTTOM), AND THEY ALL RUN THE RISK OF BURNING OUT THE THERMOCOUPLE IF YOU LET THE WATER BOIL OUT COMPLETELY

THERE ARE EVEN YOUTUBE TUTORIALS ON HOW TO MAKE ONE YOURSELF OUT OF RADIOSHACK PARTS

I FIGURE THAT IF THE THERMOCOUPLE CAN BE SHIELDED FROM CUP INTERIOR MECHANICALLY SO ITS EASY TO CLEAN -- ITS NO LOSS TO TAKE IT OVER A REGULAR POT OR CUP THAT SIZE

YOU'RE GONNA BE BOILING WATER FOR COFFEE OR SOUP OR WHATEVER ANYWAY