An electronic assembly comprising: a chassis having a plurality of electronic module mounting positions (102a- 102f), each electronic module mounting position having a chassis cooling gas passageway (103a- 103f); a respective electronic module received in each electronic module mounting position and having a module cooling gas passageway, each electronic module having a module glide surface; and a respective sealing retainer (110a - 110b) coupled between the chassis and each electronic module, the sealing retainer having a cooling gas passageway therethrough aligned with the chassis cooling gas passageway and the module cooling gas passageway, the sealing retainer comprising a retainer body having a retainer glide surface, and a gas sealing gasket carried by the retainer body; the module glide surface and the retainer glide surface having respective cooperating features so that the respective electronic module is maintained in spaced relation from the sealing gasket as the respective electronic module is slidably inserted into a seated position, wherein the electronic assembly is characterized in that the cooperating features comprise a plurality of protrusions (115a - 115f, 116a - 116f) and a plurality of valleys (117a - 117f, 120a - 120f), and one of the module glide surface and the retainer glide surface comprises the plurality of protrusions, and the other of the module glide surface and the retainer glide surface comprises the plurality of valleys, wherein the plurality of valleys is aligned with the plurality of protrusions when the electronic module is in the seated position so that respective protrusions fit into respective valleys, thereby positioning the gas sealing gasket to be seated on and around the module cooling gas passageway, and when the electronic module is being inserted into the respective electronic module mounting position of the chassis, the plurality of valleys are offset from the plurality of protrusions so that respective protrusions engage raised portions between respective valleys, thereby positioning the gas sealing gasket to be spaced apart from the module cooling gas passageway. a chassis having a plurality of electronic module mounting positions (102a- 102f), each electronic module mounting position having a chassis cooling gas passageway (103a- 103f); a respective electronic module received in each electronic module mounting position and having a module cooling gas passageway, each electronic module having a module glide surface; and a respective sealing retainer (110a - 110b) coupled between the chassis and each electronic module, the sealing retainer having a cooling gas passageway therethrough aligned with the chassis cooling gas passageway and the module cooling gas passageway, the sealing retainer comprising a retainer body having a retainer glide surface, and a gas sealing gasket carried by the retainer body; the module glide surface and the retainer glide surface having respective cooperating features so that the respective electronic module is maintained in spaced relation from the sealing gasket as the respective electronic module is slidably inserted into a seated position, wherein the electronic assembly is characterized in that the cooperating features comprise a plurality of protrusions (115a - 115f, 116a - 116f) and a plurality of valleys (117a - 117f, 120a - 120f), and one of the module glide surface and the retainer glide surface comprises the plurality of protrusions, and the other of the module glide surface and the retainer glide surface comprises the plurality of valleys, wherein a retainer body having a retainer glide surface, and a gas sealing gasket carried by the retainer body; the module glide surface and the retainer glide surface having respective cooperating features so that the respective electronic module is maintained in spaced relation from the sealing gasket as the respective electronic module is slidably inserted into a seated position, wherein the electronic assembly is characterized in that the cooperating features comprise a plurality of protrusions (115a - 115f, 116a - 116f) and a plurality of valleys (117a - 117f, 120a - 120f), and one of the module glide surface and the retainer glide surface comprises the plurality of protrusions, and the other of the module glide surface and the retainer glide surface comprises the plurality of valleys, wherein the plurality of valleys is aligned with the plurality of protrusions when the electronic module is in the seated position so that respective protrusions fit into respective valleys, thereby positioning the gas sealing gasket to be seated on and around the module cooling gas passageway, and when the electronic module is being inserted into the respective electronic module mounting position of the chassis, the plurality of valleys are offset from the plurality of protrusions so that respective protrusions engage raised portions between respective valleys, thereby positioning the gas sealing gasket to be spaced apart from the module cooling gas passageway.