While we don't yet have a dedicated case for the Behringer Xenyx Q502USB, one of the cases in our PULSE line may be a good fit!
The dimensions we have on hand for the Behringer Xenyx Q502USB are: (7.24 x 5.43 x 1.81) inches. If that aligns with what you have, we would recommend looking at the PULSE CASE FOR THE DREADBOX TYPHON: 9.75 x 5.75 x 2.25 inches.