A roller shutter (400, 500, 600, 700) including: a chamber (406, 506, 650, 750) with an opening, a roller curtain (402, 502, 608, 702, 800, 802) movable between a retracted configuration in which said roller curtain is substantially fully contained within said chamber and an extended configuration in which at least part of said roller curtain extends beyond said chamber through said opening, and at least one guide rail (408, 522, 602, 732) along and relative to which said roller curtain is movable between said retracted configuration and said extended configuration, wherein said roller curtain includes a plurality of slat members (404, 504, 611, 704, 804, 810) interlocked with each other for relative pivotal movement, said plurality of slat members collectively forming a first major surface and a second major surface, and a first layer of fire-resistant and/or heat-resistant fabric (410, 524, 612, 706, 806) fixedly mounted to said first major surface of said plurality of slat members and a second layer of fire-resistant and/or heat-resistant fabric (410, 524, 612, 708, 806) fixedly mounted to said second major surface of said plurality of slat members, characterized in that said guide rail includes at least a first sealing member (412, 526, 614) which, when said roller curtain is in said extended configuration, contacts or presses into said first layer of fire-resistant and/or heat-resistant fabric to form a first seal which at least hinders the passage of smoke there-through. a chamber (406, 506, 650, 750) with an opening, a roller curtain (402, 502, 608, 702, 800, 802) movable between a retracted configuration in which said roller curtain is substantially fully contained within said chamber and an extended configuration in which at least part of said roller curtain extends beyond said chamber through said opening, and at least one guide rail (408, 522, 602, 732) along and relative to which said roller curtain is movable between said retracted configuration and said extended configuration, wherein said roller curtain includes a plurality of slat members (404, 504, 611, 704, 804, 810) interlocked with each other for relative pivotal movement, said plurality of slat members collectively forming a first major surface and a second major surface, and a first layer of fire-resistant and/or heat-resistant fabric (410, 524, 612, 706, 806) fixedly mounted to said first major surface of said plurality of slat members and a second layer of fire-resistant and/or heat-resistant fabric (410, 524, 612, 708, 806) fixedly mounted to said second major surface of said plurality of slat members, a plurality of slat members (404, 504, 611, 704, 804, 810) interlocked with each other for relative pivotal movement, said plurality of slat members collectively forming a first major surface and a second major surface, and a first layer of fire-resistant and/or heat-resistant fabric (410, 524, 612, 706, 806) fixedly mounted to said first major surface of said plurality of slat members and a second layer of fire-resistant and/or heat-resistant fabric (410, 524, 612, 708, 806) fixedly mounted to said second major surface of said plurality of slat members, characterized in that said guide rail includes at least a first sealing member (412, 526, 614) which, when said roller curtain is in said extended configuration, contacts or presses into said first layer of fire-resistant and/or heat-resistant fabric to form a first seal which at least hinders the passage of smoke there-through.