This invention relates to a modular seating unit comprised of a plurality of chairs carried by a plurality of pedestals. The pedestals at each end of the seating unit have two casters which are movable into and out of operative position. The pedestal base may be attached to a floor by threaded bolts which are resiliently and retractably mounted to the base. Threaded bolts are supported by a coil spring which holds the bolt in an upward position to prevent damage to the threads at the end of the bolt. Threaded inserts built into the floor are color coded and are arranged in patterns which allow for placement of the seating units in various arrays. Plug-like devices are used to protect the threaded inserts and to keep debris out of the insert.