Thyroid hemiagenesis (THA) is a rare congenital anomaly in which one lobe of thyroid gland fails to develop during embryological stage. Agenesis may be unilateral. total or isthmic. Left thyroid lobe is more commonly involved than right lobe in hemiagenesis. https://www.roneverhart.com/Viking-K2-Slide-Gate-Opener-SPS-Model/