A fiber optic module (22, 22', 22", 160, 190, 220), comprising: a main body (90, 180, 210, 240) defining an internal chamber defined by a front side (96, 172, 202, 232), a rear side (98, 176, 206, 236), and opposing first and second sides (102A, 102B, 168, 170, 198, 200, 228, 230) spaced apart along a longitudinal axis on either side of the internal chamber; a plurality of optical fibers disposed in the internal chamber; a front opening (126, 178A, 178B, 208A, 208B, 238) disposed along the longitudinal axis in the front side (96, 172, 202, 232); a plurality of simplex or duplex fiber optic components (23, 150, 154) optically connected to the plurality of optical fibers, the plurality of simplex or duplex fiber optic components disposed through the front opening (126, 178A, 178B, 208A, 208B, 238); and at least one second fiber optic component (100, 152, 156, 174, 204, 234) optically connected to at least one of the plurality of optical fibers to provide optical connection between the at least one second fiber optic component and at least one of the plurality of simplex or duplex fiber optic components, wherein the at least one second fiber optic component (100, 152, 156, 174, 204, 234) is disposed through the rear side (98, 176, 206, 236) of the main body (90, 180, 210, 240); characterized in that a module rail (28A, 28B, 165A, 165B, 166A, 166B, 195A, 195B, 225A, 225B) is disposed on each of the first and second side (102A, 102B, 168, 170, 198, 200, 228, 230) of the main body (90, 180, 210, 240) and extends outwardly with respect to the internal chamber along the longitudinal axis, wherein each of the module rails (28A, 28B, 165A, 165B, 166A, 166B, 195A, 195B, 225A, 225B) is configured for installation in a corresponding module rail guide of a fiber optic equipment tray, to facilitate slideable movement of the fiber optic module (22, 22', 22", 160, 190, 220), wherein the fiber optic module (22, 22', 22", 160, 190, 220) can be installed from both a front end and a rear end of the fiber optic equipment tray; wherein the plurality of simplex or duplex fiber optic components is disposed through at least eighty-five percent of the width of the front side of the fiber optic module (22, 22', 22", 160, 190, 220); the fiber optic module further comprises a latch disposed on one of the module rails, the latch configured to engage the corresponding module rail guide of the fiber optic equipment tray, and to selectively disengage the module rail from the corresponding module rail guide; and wherein the latch is configured to disengage from the corresponding module rail guide by pushing a lever provided on the fiber optic module, and wherein the latch, the lever and the one of the module rails are provided integrally with each other. a main body (90, 180, 210, 240) defining an internal chamber defined by a front side (96, 172, 202, 232), a rear side (98, 176, 206, 236), and opposing first and second sides (102A, 102B, 168, 170, 198, 200, 228, 230) spaced apart along a longitudinal axis on either side of the internal chamber; a plurality of optical fibers disposed in the internal chamber; a front opening (126, 178A, 178B, 208A, 208B, 238) disposed along the longitudinal axis in the front side (96, 172, 202, 232); a plurality of simplex or duplex fiber optic components (23, 150, 154) optically connected to the plurality of optical fibers, the plurality of simplex or duplex fiber optic components disposed through the front opening (126, 178A, 178B, 208A, 208B, 238); and at least one second fiber optic component (100, 152, 156, 174, 204, 234) optically connected to at least one of the plurality of optical fibers to provide optical connection between the at least one second fiber optic component and at least one of the plurality of simplex or duplex fiber optic components, wherein the at least one second fiber optic component (100, 152, 156, 174, 204, 234) is disposed through the rear side (98, 176, 206, 236) of the main body (90, 180, 210, 240); characterized in that a module rail (28A, 28B, 165A, 165B, 166A, 166B, 195A, 195B, 225A, 225B) is disposed on each of the first and second side (102A, 102B, 168, 170, 198, 200, 228, 230) of the main body (90, 180, 210, 240) and extends outwardly with respect to the internal chamber along the longitudinal axis, wherein each of the module rails (28A, 28B, 165A, 165B, 166A, 166B, 195A, 195B, 225A, 225B) is configured for installation in a corresponding module rail guide of a fiber optic equipment tray, to facilitate slideable movement of the fiber optic module (22, 22', 22", 160, 190, 220), wherein the fiber optic module (22, 22', 22", 160, 190, 220) can be installed from both a front end and a rear end of the fiber optic equipment tray; wherein the plurality of simplex or duplex fiber optic components is disposed through at least eighty-five percent of the width of the front side of the fiber optic module (22, 22', 22", 160, 190, 220); the fiber optic module further comprises a latch disposed on one of the module rails, the latch configured to engage the corresponding module rail guide of the fiber optic equipment tray, and to selectively disengage the module rail from the corresponding module rail guide; and wherein the latch is configured to disengage from the corresponding module rail guide by pushing a lever provided on the fiber optic module, and wherein the latch, the lever and the one of the module rails are provided integrally with each other.