This is the Steel Case Tube fitted to numerous Seamaster models, please view images to identify if it's correct as Omega specify 2 or 3 of these for similar models.
165.1503, 168.1502, 168.1502NUM, 168.1503, 168.1503NUM, 168.1506, 168.1507, 168.1602, 168.1603, 168.1617, 168.1622, 168.1623, 168.1626, 168.1627, 168.1628, 168.1629, 168.1630, 168.1631, 168.1632, 168.1633, 168.1634, 168.1635, 168.1636, 168.1637, 168.1638, 168.1640, 168.1641, 168.1642, 168.1643, 168.1645, 168.1648, 168.1649, 168.1650, 168.1651, 168.1652, 168.1653, 168.1656, 168.1657, 168.1658, 168.1659, 168.1660, 168.1661, 168.1663, 1681626, 175.0514, 178.0504, 178.0514, 178.0515, 178.0516, 178.0520, 178.0521, 178.0522, 178.0523, 178.0524, 196.1502, 196.1502NUM, 196.1502OLY, 196.1503, 196.1503NUM, 196.1503OLY, 196.1504, 196.1505, 196.1507, 196.1508, 196.1522, 196.1523, 196.1524, 196.1525, 196.1640, 196.1641, 1961522, 268.1650, 268.1651, 268.2050, 268.2050X, 268.2052, 268.2053, 268.2054, 268.2055, 268.2060, 268.2060X, 268.2062, 268.2063, 268.2064, 268.2065, 368.1502, 368.1503, 3681502, 396.1502, 396.1503
These are genuine Omega supplied service case tubes.
 
Stainless Steel Threaded