A nut assembly for use in a fluid tight assembly, wherein said fluid tight assembly comprises a first conduit having a first distal end and a second conduit having a first threaded portion, wherein the nut assembly comprises: a nut which has a nut body (22; 22a; 22b; 22c), in particular a nut which consists of a nut body (22; 22a; 22b; 22c), wherein the nut is configured to be received on the first end of the first conduit and wherein the nut has a second threaded portion which can be caused to be in engagement with the first threaded portion of the second conduit; a visual indicator (40; 50; 60; 62), in particular coupled to the nut, wherein the visual indicator has a first state in which an indicator portion of the visual indicator is out of view from the exterior of the nut, and a second state in which the indicator portion of the visual indicator is visible from the exterior of the nut when the fluid tight assembly is fully tightened, characterised in that a) the visual indicator comprises at least one leg (44; 54) disposed within the nut, wherein the leg is transferred between the first state and the second state by an engagement with the first conduit, wherein the at least one leg is deflected into the second state by engagement with the first conduit when the fluid tight assembly is fully tightened, and I or wherein the at least one leg has the shape of a bent L having a first portion with a distal end that engages the first conduit, or in that b) the visual indicator comprises: an annular ring which is received within the nut; an elastomeric indicator portion which is disposed on the annular ring and which has a central portion which extends radially inwardly with respect to the ring; wherein the central portion is disposed between the first conduit and the nut in an installed state of the assembly; and wherein the elastomeric indicator portion is compressed by the first conduit in the second state in such a way that the central portion is forced towards a position in which it is visible from the exterior of the nut. a nut which has a nut body (22; 22a; 22b; 22c), in particular a nut which consists of a nut body (22; 22a; 22b; 22c), wherein the nut is configured to be received on the first end of the first conduit and wherein the nut has a second threaded portion which can be caused to be in engagement with the first threaded portion of the second conduit; a visual indicator (40; 50; 60; 62), in particular coupled to the nut, wherein the visual indicator has a first state in which an indicator portion of the visual indicator is out of view from the exterior of the nut, and a second state in which the indicator portion of the visual indicator is visible from the exterior of the nut when the fluid tight assembly is fully tightened, characterised in that a) the visual indicator comprises at least one leg (44; 54) disposed within the nut, wherein the leg is transferred between the first state and the second state by an engagement with the first conduit, wherein the at least one leg is deflected into the second state by engagement with the first conduit when the fluid tight assembly is fully tightened, and I or wherein the at least one leg has the shape of a bent L having a first portion with a distal end that engages the first conduit, or in that b) the visual indicator comprises: an annular ring which is received within the nut; an elastomeric indicator portion which is disposed on the annular ring and which has a central portion which extends radially inwardly with respect to the ring; wherein the central portion is disposed between the first conduit and the nut in an installed state of the assembly; and wherein the elastomeric indicator portion is compressed by the first conduit in the second state in such a way that the central portion is forced towards a position in which it is visible from the exterior of the nut. a) the visual indicator comprises at least one leg (44; 54) disposed within the nut, wherein the leg is transferred between the first state and the second state by an engagement with the first conduit, wherein the at least one leg is deflected into the second state by engagement with the first conduit when the fluid tight assembly is fully tightened, and I or wherein the at least one leg has the shape of a bent L having a first portion with a distal end that engages the first conduit, or in that b) the visual indicator comprises: an annular ring which is received within the nut; an elastomeric indicator portion which is disposed on the annular ring and which has a central portion which extends radially inwardly with respect to the ring; wherein the central portion is disposed between the first conduit and the nut in an installed state of the assembly; and wherein the elastomeric indicator portion is compressed by the first conduit in the second state in such a way that the central portion is forced towards a position in which it is visible from the exterior of the nut. an annular ring which is received within the nut; an elastomeric indicator portion which is disposed on the annular ring and which has a central portion which extends radially inwardly with respect to the ring; wherein the central portion is disposed between the first conduit and the nut in an installed state of the assembly; and wherein the elastomeric indicator portion is compressed by the first conduit in the second state in such a way that the central portion is forced towards a position in which it is visible from the exterior of the nut.