Headsets that leave the ear canal open are used where environmental noise and acoustical information have to be maintained, while additional sound transmission is also required. Besides classical supra aural and in-ear phones having “hear through” functions, bone conduction and “tube-like” headsets inserted in the ear canal can be used. Usually, the transfer parameters of these devices are inferior to traditional headphones, providing decreased sound quality, sensitivity and speech intelligibility. Two different commercially available bone conduction headphones, an in-ear tube type earphone and supra aural models were tested using a dummy-head and a real human head for comparison. Measured transfer functions show the limited frequency range of open ear canal models that restricts the accessibility of such devices. Variability in repeated measurements is relatively large. Standardization of the measurement procedure for bone conduction headsets is needed, where the inclusion of human subjects can be considered.