In 2006, Pilot Pens Inc. developed a pen with erasable ink that utilized thermochromic ink. It was composed of a solvent, a colorant, and a resin film-forming agent. At temperatures below 65 °C, the ink stayed in a colored state. Once temperatures went above 65 °C, the ink began to melt and became colorless, creating the effect of erasable ink. The ink was able to return to its colored state by cooling the temperature down to below -10 °C.