Here is a stethoscope that connects to your phone to visualize your heart sound waveform. The 3M Littmann CORE comes with 4x amplification and active noise cancellation. It has analog and amplified listening modes.
This stethoscope has soft-sealing ear tips and dual-sided stainless steel chest piece. You will be able to use it to save 15 to 120-second recordings. The 3M Littmann CORE stethoscope is compatible with iOS and Android devices.