The said industrial design consists of the shape and configuration of the bath tub as shown in the drawings; the first variant of the bath tub presents a bath tub tray having a base portion, front and rear walls, and side walls; the front wall presents a large U-shaped opening therein; the first variant of the bath tub tray presents a flat upper surface extending continuously along the front, side and rear walls on either side of the U-shaped opening and has curved inner corner areas; the rear upper surface has a narrow left side portion and a wider right side portion with an angled transition area between the two portions; the outer surfaces of the front and side walls of the first variant have a continuous horizontal stepped section part way along the height thereof; the bath tub also presents a generally rectangular transparent door with rounded lower and upper right corners; the door extends above the bath tub tray generally in line with and slightly wider than the U-shaped opening; a door support structure presents a transparent rectangular panel that extends upwards part way along the height of and spaced slightly apart from the left side edge of the door; the locking device presents a flat rectangular lower element with a raised rectangular element thereon and an elongated left side element extending upwards therefrom; the second variant of the bath tub presents a bath tub tray having a base portion, front and rear walls, and side walls; the front wall presents a large U-shaped opening therein; the tub tray presents a flat upper surface extending continuously along the front, side and rear walls on either side of the U-shaped opening and has curved inner corner areas; the rear upper surface is of constant width along its length; the outer surface of the front and side walls of the second variant are generally flat; the bath tub also presents a generally rectangular transparent door with rounded lower and upper right corners; the door extends above the bath tub tray generally in line with and slightly wider than the U-shaped opening; a door support structure presents a transparent rectangular panel that extends part way along and spaced slightly apart from the left side edge of the door and extends upwards from the flat upper left side surface of the front wall; the locking device presents a flat rectangular lower element extending along the upper right surface of the front wall with a raised rectangular element thereon and an elongated left side element extending upwards therefrom; the third variant of the bath tub presents a bath tub tray having a base portion, front and rear walls, and side walls; the front wall presents a large U-shaped opening therein; the tub tray presents a flat upper surface extending continuously along the front, side and rear walls on either side of the U-shaped opening and has curved inner corner areas; the rear upper surface has a narrow left side portion and a wider right side portion with an angled transition area between the two portions; the outer surface of the front wall has a stepped vertical area extending the height thereof; the bath tub also presents a generally rectangular transparent door with rounded lower and upper right corners; the door extends above the bath tub tray generally in line with and slightly wider than the U-shaped opening; a door support structure presents a transparent rectangular panel that extends part way along and spaced slightly apart from the left side edge of the door and extends upwards from the flat upper left side surface of the front wall; the locking device presents a flat rectangular lower element extending along the flat upper right surface of the front wall with a raised rectangular element thereon and an elongated left side element extending upwards therefrom; the fourth variant of the bath tub presents a bath tub tray having a base portion, front and rear walls, and side walls; the front wall presents a large U-shaped opening therein; the tub tray also presents a flat upper surface extending continuously along the front, side and rear walls on either side of the U-shaped opening and has curved inner corner areas; the rear upper surface has a slightly outwardly curved inside edge; the outer surface of the front wall has a vertical double lined area extending the height thereof; the bath tub also presents a generally rectangular transparent door with rounded lower and upper right corners; the door extends above the bath tub tray generally in line with and slightly wider than the U-shaped opening; a door support structure presents a transparent rectangular panel that extends part way along and spaced slightly apart from the left side edge of the door and extends upwards from the flat upper left side surface of the front wall; the locking device presents a flat rectangular lower element extending along the upper right surface of the front wall with a raised rectangular element thereon and an elongated left side element extending upwards therefrom.Representations of the design are shown in the figures wherein:Fig. 1 is a front perspective view of a first variant of the design of a bath tub with a door and locking device;Fig. 2 is a front perspective view of a second variant of the design of a bath tub with a door and locking device;Fig. 3 is a front perspective view of a third variant of the design of a bath tub with a door and locking device; andFig. 4 is a front perspective view of a fourth variant of the design of a bath tub with a door and locking device.Diagrams of the design are included.