Series 6500 This series of hermetic connector meets or exceeds the requirements of MIL-DTL-83723 Series III, threaded style coupling and M8372388, M8372389 and M8372390. This specification is an upgrade to MIL-DTL-26500 and has the same mounting dimensions.Series 6600 This series of hermetic connector meets or exceeds the requirements of MIL-DTL-83723 Series III, bayonet style coupling and M8372379, M8372380, M8372381, M8372393 and M8372394.