Hi, i’ve found another video https://www.youtube.com/watch?v=UNuppIDDHFU# here you can see it’s a new exclusive feature for the DJM-900NXS, so if you have another mixer it doesn’t work.
You can use also the Launoupad app,i’ve updated the app for iPad and now (for 2,99€) you can send MIDI signal so i think it can be synced with MIDI devices/other apps/DAW/DJ software, so you can use to launch clip and keep in sync with other devices you uses, i don’t know the potential of this app but it looks great.