This set includes NE555 Timers, LM324 Amplifiers, 8-bit Shift Registers, Quadruple Bus Buffer Ports, L293D Motor Drivers and Darlington ULN2003 and ULN2803 Transistor Arrays.
The LM339 is an LMx39x Series Voltage Comparator IC and is manufactured by many industries. The devices consist of four independent voltage comparators designed to operate from a single power supply. Operation with dual supplies is also possible as long as the difference between the two supplies is from 2V to 36V.
The Arduino WTV020-SD MP3 Module is a voice recording module with 1GB SD Card storage capacity. You can upload WAV and AD4 format files that conform to FAT formatting. It supports 6KHz to 32KHz, being 36KHz for AD4 files and 6-16KHz for voice sampling rate (Audio Sampling).