also incorporated herein by reference behind the elastomerica strip 14 the front frame member 11 defines a backstop 16 which serves an important role in establishing certain parameters of the shaving geometry of the blade unit and in particular the blade span s 1 of the first blade which is measured from the top rear edge 17 of the backstop 16 the rear member 12 of the frame carries a lubricating strip 18 incorporating a lubricant which is leached out of the strip on contact with water the composition of the lubricating strip 18 may be as described in u s pat no 5 113 585 the contents of which are incorporated herein by reference mounted within the central opening of the frame are three blade assemblies providing first second and third blades 19 20 21 with parallel forwardly directed cutting edges 24 25 26 each blade 19 20 21 consists of a substantially planar metal strip fixed e g spot welded to a support bar 28 the blade support bar 28 has parallel front and rear faces 30 and 31 a bottom face 32 which is perpendicular to the front and rear faces and a top face 33 to which the blade is attached and which is forwardly and upwardly inclined the angle between the front and top faces being about 67 5 u00b0 so that the blade is inclined at an angle of about 22 5 u00b0 the support bar 28 has downwardly directed legs 29 at its ends these legs being slidably received in slots 35 formed in the inner faces of the frame ends 13.