Comparison of the candidate pulsating O-type stars with the theoretical instability strips for ℓ = 0 − 2 and three different metallicities Z_ini = 0.010, 0.014, 0.020 (same figure style as Fig. 13). The size of the symbol is proportional to the projected rotational velocity of the star which ranges between v sin i = 26 − 291 km s⁻¹. Hatched symbols mark variable stars where the exact contribution of g modes, rotational variability, and SLF is difficult to disentangle.