The Controllersist Bag is quite versatile and can hold multiple devices at once. You can easily Fit Kontrol S2/S4/Z2 Pioneer DDJ-SB/SR along with your headphones, laptop, cables and a secondary device such as Push, Maschine, DDJ-SP1, Pioneer RMX-500/1000, 2 Kontrol X1/Z1/F1 or multiple Midi Fighters.
This bag is not big enough for larger controllers such as Pioneer DDJ-SX/SZ, Vestax VCI-400 or Numark NS6/7. While some of these might fit they are just too heavy and will damage the bag in a short term.