NH15 SII Automatic Watch Movement NH15 is a SII product manufactured by the Seiko Group of Companies. This is a self-winding (Automatic) watch movement, 3 hands (hour/minute/sweep second), 10 1/2 ligne, with a diameter of 23.80 mm and a movement height of 6.01 mm. This is a 21 jewel movement with a date window at the 3 o'clock position. Hand dimensions: 100/65/21 (hour/minute/sweep second). Stem is a part number 351-420.