A feedthrough, comprising: first and second parts (202, 204), each including a flange (206, 208) with an opening, therethrough, and a tubular segment (214, 216) extending normally from a first surface of the flange and having a lumen (222, 224) disposed generally concentrically with the opening (210, 212); and a pair of complementary engaging mechanisms (226, 228), each disposed on a distal end portion of a respective one of the tubular segments (214, 216) and configured to couple the first and second parts (202, 204) together through an opening in a panel having opposite sides in a snap-together fashion, such that: the first surface (218, 220) of each of the flanges (206, 208) is held adjacent to a corresponding one of the opposite surfaces of the panel; and the lumens (222, 224) of respective ones of the tubular segments are disposed generally concentrically with each other, wherein the distal end portion of the tubular segment of the second part is provided with a tapered surface configured such that, when it is pushed into abutment with an opposing surface of the distal end of the tubular segment of the first part, the tapered surface compresses or deflects the side walls of the distal end portion of the tubular segment of the second part radially inward, and/or expands the side walls of the distal end portion of the tubular segment of the first part radially outward, wherein the feedthrough further comprises an indexing mechanism configured to orient the first and second parts (202, 204) at a selected angular position relative to each other when the first and second parts are coupled together through the opening. first and second parts (202, 204), each including a flange (206, 208) with an opening, therethrough, and a tubular segment (214, 216) extending normally from a first surface of the flange and having a lumen (222, 224) disposed generally concentrically with the opening (210, 212); and a pair of complementary engaging mechanisms (226, 228), each disposed on a distal end portion of a respective one of the tubular segments (214, 216) and configured to couple the first and second parts (202, 204) together through an opening in a panel having opposite sides in a snap-together fashion, such that: the first surface (218, 220) of each of the flanges (206, 208) is held adjacent to a corresponding one of the opposite surfaces of the panel; and the lumens (222, 224) of respective ones of the tubular segments are disposed generally concentrically with each other, wherein the distal end portion of the tubular segment of the second part is provided with a tapered surface configured such that, when it is pushed into abutment with an opposing surface of the distal end of the tubular segment of the first part, the tapered surface compresses or deflects the side walls of the distal end portion of the tubular segment of the second part radially inward, and/or expands the side walls of the distal end portion of the tubular segment of the first part radially outward, wherein the feedthrough further comprises an indexing mechanism configured to orient the first and second parts (202, 204) at a selected angular position relative to each other when the first and second parts are coupled together through the opening. the first surface (218, 220) of each of the flanges (206, 208) is held adjacent to a corresponding one of the opposite surfaces of the panel; and the lumens (222, 224) of respective ones of the tubular segments are disposed generally concentrically with each other, wherein the distal end portion of the tubular segment of the second part is provided with a tapered surface configured such that, when it is pushed into abutment with an opposing surface of the distal end of the tubular segment of the first part, the tapered surface compresses or deflects the side walls of the distal end portion of the tubular segment of the second part radially inward, and/or expands the side walls of the distal end portion of the tubular segment of the first part radially outward, wherein the feedthrough further comprises an indexing mechanism configured to orient the first and second parts (202, 204) at a selected angular position relative to each other when the first and second parts are coupled together through the opening.