A pair of ram blocks are provided such that when they are actuated hydraulically to move together, they present an opening which has a series of gripping members downwardly biased. Removal of tubulars or tools from the well bore works against the bias to retract the grippers so that removal can be accomplished. However, if there is an accidental release, the bias pushes the grippers toward the tubular or tool to grip it to prevent loss into the well bore. The ram blocks can be retracted for run-in to the well bore.