The portrait of Benjamin Franklin on the $100 bill is visible from both sides when held in light, and the note has an estimated lifespan of 15 years, according to the United States Currency Education Program. In 2013, the Department of the Treasury redesigned the $100 note adding new security features. It is the highest valued bill in circulation, as of 2015, and like all other U.S. notes, it weighs 1 gram.
The vignette on the reverse side of the bill is of the Independence Hall in Philadelphia, Pennsylvania, and the hands of the clock are set to 4:10. The Bureau of Engraving and Printing has no record of why the note displays this particular time.
The Federal Reserve put the redesigned $100 note into circulation on October 8, 2013. Some security features of the 2013 note include color-shifting ink, a 3D security ribbon and tiny microprinting on the note. Microprinting on the U.S. $100 note first appeared on the 1990 series. One pound of U.S. currency would contain 454 notes, no matter the denomination, because all U.S. notes weigh one gram. All U.S. bank notes are 25 percent linen and 75 percent cotton, and an estimated value of two-thirds of all U.S. currency is in circulation outside of the U.S.