The objective is to conduct detailed experimental studies of a single rabbit RBC in micro-channels in a planar linear flow. For this purpose we are utilizing a four-roll mill geometry micro-channel, which is versatile and advantageous in its ability to exhibit different flows, ranging from rotation through shear to elongation by controlling a single control parameter, namely the pressure drop between the inlets and outlets. This dynamical trap was used just recently in our experiment on a single vesicle dynamics to study the phase diagram of different dynamical regimes. The main goal of the experiment is to investigate the RBC in-shear-plane dynamics in a linear flow and to quantitatively characterize the RBC dynamical regimes such as tumbling, tank-treading, swinging and intermediate. The latter is still a subject for controversy in both experiment and simulations and requires thorough studies.