The Craftsman 4 mm easy-to-read Socket， 6-point. Metric， 1/4 inch drive designed with a headlock grip， the Craftsman 4 mm easy-to-read Socket， 6-point metric， 1/4 inch drive provides extra contact on the flats of the fastener for extra turning force. The small size delivers optimal precision and accuracy when working with the delicate hardware. Laser-etched size markings that make it easy to locate in your box low-lit or greasy environments.