blade package should contribute from 20 to 25 of the 75 to 90 gram force this is obtained by creating a blade package which flexes in the same locations as the seat and the cap and which has covering between about 15 and about 30 of the surface of the package as can be seen particularly by reference to fig2 the seat blade is actually larger than the cap blade it is particularly preferred that the seat blade have an open area of about 25 to about 30 the cap blade should have about 20 to 25 open area deflection values are determined as discussed below the purpose of these tests was to compare the stiffness characteristics of the blade cartridge of this invention and the razor described in motta et al and cartright patents referring to fig1 the blade cartridge is held in a fixture which is rigidly attached to an instron tensile tester base a ram fixture as its name depicts is kinematically mounted to the movable ram of the instron and is hung from a calibrated load cell at the bottom of the ram fixture is a pin which applies a load to the blade cartridge in the cartridge holder as the ram fixture moves upward the purpose of this system is to apply a known deflection to the blade cartridge and simultaneously measure the force tabulated below are the.