4.1.1 The production model of add-on equipment,
                           for which the approval will apply, should be identical to the equipment,
                           type-tested in accordance with the performance and test specifications
                           contained in part 1 or 2 of the annex to these Guidelines. The equipment
                           should also be type-tested in accordance with the specifications for
                           environmental testing contained in part 3 of the annex to resolution MEPC.107(49).
                           
                        
                        
                        
                      
                     
                     
                     
                        
                        
                         
                           4.1.2 Where a range of add-on equipment of the
                           same design, but of different capacities, requires certification in
                           accordance with these specifications, the Administration may accept
                           tests in two capacities within the range, in lieu of tests on every
                           size, providing that the two tests actually performed are from the
                           lowest quarter and highest quarter of the range.