A hair brush comprising an elongate body including a utility portion and a handle portion at opposite ends thereof and defining a longitudinal axis, wherein the utility portion includes a back member acting as a support from which brushing projections extend, and defines a first plane and a second plane perpendicularly intersecting the first plane, wherein the back member is flexibly movable with respect to the handle portion on the first plane and the second plane, characterized in that : - the utility portion further includes a pair of spines arranged at opposite sides of the back member for further controlling the flexible movement of the back member whereby the extent of control of movement of the back member by the spines are either limited to the movement on only the first plane or substantially more on the first plane than the second plane; and - the utility portion is configured to flex sideways departing from the longitudinal axis thereof, and the degree of flexing ranges from substantially 2° to 30°, - wherein i) the back member and the spines are integrally formed in one injection molding step and/or formed of one plastic(s) material; or ii) the back member is formed from a first injection molding step using a first plastic(s) material and is provided with two sets of channels arranged on the opposite lateral sides of the back member and running along the longitudinal length of the back member , and the pair of spines is formed from a second injection molding step using a second plastic(s) material running through the two sets of channels. - the utility portion further includes a pair of spines arranged at opposite sides of the back member for further controlling the flexible movement of the back member whereby the extent of control of movement of the back member by the spines are either limited to the movement on only the first plane or substantially more on the first plane than the second plane; and - the utility portion is configured to flex sideways departing from the longitudinal axis thereof, and the degree of flexing ranges from substantially 2° to 30°, - wherein i) the back member and the spines are integrally formed in one injection molding step and/or formed of one plastic(s) material; or ii) the back member is formed from a first injection molding step using a first plastic(s) material and is provided with two sets of channels arranged on the opposite lateral sides of the back member and running along the longitudinal length of the back member , and the pair of spines is formed from a second injection molding step using a second plastic(s) material running through the two sets of channels. i) the back member and the spines are integrally formed in one injection molding step and/or formed of one plastic(s) material; or ii) the back member is formed from a first injection molding step using a first plastic(s) material and is provided with two sets of channels arranged on the opposite lateral sides of the back member and running along the longitudinal length of the back member , and the pair of spines is formed from a second injection molding step using a second plastic(s) material running through the two sets of channels. <EOS>