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Premium Automatic Mechanical Double Flywheel Watch with 31 JewelsDouble Flying Wheels doubles the fun with two operating in a mesmerizing display on the bottom half of the watch, while also contributing to the precision of the timekeeping with 31 Jewels. EXQUISITE DETAIL WITH DOUBLE FLYING WHEELSGENUINE LEATHER BAND WITH BUTTERFLY CLIP The photos were taken by me. Not graphically altered in anyway. Actual watch that you will receive. COLOR: SILVER WITH GREEN GENUINE LEATHER BAND (20mm) WITH BUTTER FLY CLIPWATCH CASE SIZE: 41MMDISPLAY: ANALOGCASE: STAINLESS STEELMOVEMENT: AUTOMATIC MECHANICAL WITH DOUBLE FLYWHEEL & 31 JEWELSGLASS: SAPPHIREWATER RESISTANCE RATING: 3ATM (30 METERS)PACKAGE INCLUDES: WATCH, MANUAL INSTRUCTION, WATCH BOXNOTE: DIALS, DOUBLE FLYWHEEL ARE ALL FUNCTIONAL.Automatic mechanical watch's momentum comes from the wearer's movement. So wear under normal circumstances. Don't need hand winding. Only when the wearer couldn't provide enough momentum.