- The 35803 dash numbers correspond with 
                                the last three digits of the O'ring part numbers.
 
                              - 6244 dash numbers correspond with 
                                6230 series O'rings.
 
                              - 6246 dash numbers correspond with 
                                6227 series O'rings.
 
                              - 28777 (6291) dash numbers correspond 
                                with 6290 series O'rings.
 
                             
                              Back-Up Rings extend the service life of the 
                                o'rings and also extend the pressure range over which synthetic 
                                rubber o'rings perform their sealing function. They prevent 
                                o'ring extrusion and nibbling and should be used where large 
                                clearance gaps or high pressures are necessary. 
                              Leather Back-Up Rings may be used in all packing 
                                applications. They are high in tensile strength and resistant 
                                to heat and wear. Leather has a range of -30 degrees F to 
                                +150 degrees F.   |