In research and development in general, and in user-centered design (UCD) in particular, study participants have to be representative for the target audience. However, given the voluntary participation in user studies and an ensuing self-selection bias, participants of user studies likely prefer to engage with technology more strongly than the target audience in general (i.e., they have a higher affinity for technology interaction, ATI). Unchecked, this potential bias might lead to products that neglect important user groups or miss valuable market niches. At the same time, participants' time is limited, so assessment of ATI must be economical. Thus, we propose an ultra-short ATI scale derived from the ATI scale by [10]. ATI-S was developed using theoretical considerations and empirical analyses. It provides a sufficiently reliable and valid assessment of ATI for conditions with strict time-constraints, in which the full ATI scale cannot be used.