The STM3400 is a 2-channel mixer for the starting and the more experienced DJ. Featuring a USB/SD input to play MP3s directly from a USB stick or SD-card. The mixer is also equipped with a BT receiver so you can stream music directly from your smartphone or other BT enabled device. There are two additional options compared to other standard DJ mixers: 1) A built-in Jog Wheel for scratching your favourite music (via the master output) 2) Internal DSP-effect unit with 16 effects.