The Model 4D LHe Level Sensor has an outside diameter of 9.52 mm O.D. (3/8″). It is available in active sensing lengths of 110 to 200 cm. Overall length (OAL) is 2 cm longer than the active sensing length (1 cm dead space on either end). The sensor is supplied with 4 teflon-insulated hookup leads 30 cm in length. Please specify active sensing length on order.