A system, comprising an autonomous seismic node for deployment to the seabed and an external device, the autonomous seismic node comprising: a pressure housing for an autonomous seismic node , wherein at least one seismic sensor , at least one data recording unit , and at least one clock are located within the pressure housing , wherein the autonomous seismic node is configured to land on the seabed; and a bulkhead connector coupled to the pressure housing configured to receive an external device, wherein the bulkhead connector comprises: a cylindrical housing that forms an inner cavity and a connector insert , wherein the connector insert comprises: a flat contact surface ; and a plurality of pins configured to transfer power or data with the external device, wherein each pin comprises a flat electrical contact surface configured to be substantially flush with the flat contact surface , characterised in that : the external device comprises a sealing element (528; 728); the bulkhead connector is configured for subsea use; and the inner cavity is configured to receive said sealing element (528; 728) located on the external device. an autonomous seismic node for deployment to the seabed and an external device, the autonomous seismic node comprising: a pressure housing for an autonomous seismic node , wherein at least one seismic sensor , at least one data recording unit , and at least one clock are located within the pressure housing , wherein the autonomous seismic node is configured to land on the seabed; and a bulkhead connector coupled to the pressure housing configured to receive an external device, wherein the bulkhead connector comprises: a cylindrical housing that forms an inner cavity and a connector insert , wherein the connector insert comprises: a flat contact surface ; and a plurality of pins configured to transfer power or data with the external device, wherein each pin comprises a flat electrical contact surface configured to be substantially flush with the flat contact surface , a pressure housing for an autonomous seismic node , wherein at least one seismic sensor , at least one data recording unit , and at least one clock are located within the pressure housing , wherein the autonomous seismic node is configured to land on the seabed; and a bulkhead connector coupled to the pressure housing configured to receive an external device, wherein the bulkhead connector comprises: a cylindrical housing that forms an inner cavity and a connector insert , wherein the connector insert comprises: a flat contact surface ; and a plurality of pins configured to transfer power or data with the external device, wherein each pin comprises a flat electrical contact surface configured to be substantially flush with the flat contact surface , a cylindrical housing that forms an inner cavity and a connector insert , wherein the connector insert comprises: a flat contact surface ; and a plurality of pins configured to transfer power or data with the external device, wherein each pin comprises a flat electrical contact surface configured to be substantially flush with the flat contact surface , a flat contact surface ; and a plurality of pins configured to transfer power or data with the external device, wherein each pin comprises a flat electrical contact surface configured to be substantially flush with the flat contact surface , the external device comprises a sealing element (528; 728); the bulkhead connector is configured for subsea use; and the inner cavity is configured to receive said sealing element (528; 728) located on the external device. <EOS>