This part of IEC 60286 describes the common dimensions, tolerances and characteristics of the tray. It includes only those dimensions which are essential for the handling of the trays for the stated purpose and for placing or removing components from the trays. Matrix trays are designed to facilitate the transport and handling of electronic components during their testing, baking, transport/storage, and final mounting by automatic placement equipment. The generic rules for their design are given in this standard.. Newly developed trays which follow these rules will not be listed individually . Only those trays which conform to the design rules set forth herein are classified as “standard trays” and are thus preferred for use. NOTE Matrix trays listed in Annex A which do not conform to the design rules set forth herein shall be considered as “non-standard trays” and are not preferred for use.