The ROK-IT gauge with its true spherical form eliminates the difficulties and limitations encountered in the use of the conventional type of "plug" gauge which has maximum or excess frictional area contact with the work. It will positively "accept" or "reject" down to the tightest limits. It is extremely light and easy to handle. 100mm diameter double ended gauge weighs 500g. Sizes available up to 22"/559mm. Calibration certificates available at extra cost.