In a ball circulating groove structure of a ball nut, a deflector is provided with an inner collar extending along a penetrating direction of a hole of the ball nut and engaging with the ball nut in a side of an inner surface of the ball nut, and an outer collar engaging with the ball nut in a side of an outer surface of the ball nut. In some examples, these deduplication techniques involve fingerprinting file system elements that are being shared and transferred, and dividing each file into separate units referred to as \u201cblocks\u201d or \u201cchunks. Significant parts of these devices include the microprocessor and stored instructions, or algorithms, that govern how the devices interpret and react to electrical signals indicative of normal or abnormal heart rhythms.