Early Mini runner for metal type window catches pre May 1963 with sliding windows on the front doors, these are the runners that hold the channel and have holes to lock the window catches. Now made in stainless steel by Minispares to ease rust problems. Also see
14A6770 for L/H.
Best to fit a pair so they look the same-Plastic catches were supposedly fitted from chassis number 15069 early may 1963 and the runners changed to 24A1303.