A powered air respirator kit for use with a safety helmet comprising a visor removably attachable to a front edge of the safety helmet, a drive unit removably attachable to said safety helmet, at least one filter module removably attachable to said safety helmet such that, in use, a fluid flow path is defined through said filter module to a space defined between a user's face and an inner surface of said visor, characterised in that the kit further comprises a power module removably attachable to said safety helmet and, in use, electrically connectable to said drive unit; a gasket which is removably attachable to a front edge of said safety helmet, and a pair of adaptors, each being removably connectable to a side surface of said safety helmet, and an elongate visor carrier member on which said visor can be mounted and having, at each distal end thereof, connector members configured, in use, to pivotally engage with respective said adaptors, wherein said visor carrier comprises a curved band configured, in use, to be connected to said front edge of said safety helmet; wherein said visor carrier comprises a peaked portion extending substantially horizontally from a generally central portion of said band, wherein, in use, said visor extends downwardly from said band such that a first portion of said peaked portion extends beyond a front edge of said visor and a second portion of said peaked portion extends between the rear of the band and the front edge of the safety helmet; and wherein said second portion of said peaked portion of said visor carrier includes at least one opening therein, and said gasket is configured to, in use, removably receive said drive unit such that a fluid flow path is defined between said at least one filter module and said opening, said opening being provided with a guidance duct configured to direct air away from a user's eyes onto a rear surface of said visor, in use. a visor removably attachable to a front edge of the safety helmet, a drive unit removably attachable to said safety helmet, at least one filter module removably attachable to said safety helmet such that, in use, a fluid flow path is defined through said filter module to a space defined between a user's face and an inner surface of said visor, characterised in that the kit further comprises a power module removably attachable to said safety helmet and, in use, electrically connectable to said drive unit; a gasket which is removably attachable to a front edge of said safety helmet, and a pair of adaptors, each being removably connectable to a side surface of said safety helmet, and an elongate visor carrier member on which said visor can be mounted and having, at each distal end thereof, connector members configured, in use, to pivotally engage with respective said adaptors, wherein said visor carrier comprises a curved band configured, in use, to be connected to said front edge of said safety helmet; wherein said visor carrier comprises a peaked portion extending substantially horizontally from a generally central portion of said band, wherein, in use, said visor extends downwardly from said band such that a first portion of said peaked portion extends beyond a front edge of said visor and a second portion of said peaked portion extends between the rear of the band and the front edge of the safety helmet; and wherein said second portion of said peaked portion of said visor carrier includes at least one opening therein, and said gasket is configured to, in use, removably receive said drive unit such that a fluid flow path is defined between said at least one filter module and said opening, said opening being provided with a guidance duct configured to direct air away from a user's eyes onto a rear surface of said visor, in use.