Most Popular Timers or RTCs DS3234SN# DS3234SN#T& R DS3234S# DS3234SN# DS3231SN# DS1682S+ DS1682S+T& R DS3234S#T& R DS3234SN#T& R DS3231SN#T& R DS1682S PCF8563T/5, 518 DS3231MZ+ DS3231MZ+TRL M41T81M6F DS1682S+ PCF8563TS/5, 118 DS1307ZN+ DS1302ZN+T& R DS1307ZN+T& R DS1338Z-33+T& R PCF2129T/2, 518 PCF8563TS/4, 118 M4T32-BR12SH1 DS1307Z+T& R DS3231M+TRL DS1307Z+ RTC-72423A PCF8563T/F4, 118 DS1682S/T& R