Calibre OP IV "high beat" Zenith El Primero base 31 jewels the black dial with luminescent Arabic numerals three subdials for small seconds minute and hour counters aperture for the date in three-part case polished bezel with tachymetric scale screw-down transparent back two chronograph pushers in the band trademark crown protecting bridge with lock lever stainless steel Panerai double deployant clasp case dial and movement signed.