See 2.5.3.2.5 of the IMDG Code:

"Classification of organic peroxides not listed in 2.5.3.2.4 packing instruction IBC520 or portable tank instruction T23 and assignment to a generic entry shall be made by the competent authority of the country of origin on the basis of a test report. Principles applying to the classification of such substances are provided in 2.5.3.3. Test methods and criteria and an example of a report are given in the current edition of the Manual of Tests and Criteria, part II. The statement of approval shall contain the classification and the relevant transport conditions (see 5.4.4.1.3).[...]"

This BAM No. represents the collective entry itself -  has been assigned packing method OP5 according to 4.1.7.1.4.1 of the IMDG Code. A packing method with a lower OP number may be indicated in the approval certificate of the competent authority if the organic peroxide meets the criteria of 2.5.3.3.2.2 only in a smaller packaging.

Under certain circumstances, the hazard label according to model 1 may be omitted (see special provision 181).