Radio-immunoassay kits exemption clarified: applies only to radio based hormone and Digoxin kits, not all immunoassays. The circular clarifies that the customs exemption applies only to Radio-immunoassay kits for the enumerated hormones and Digoxin and not to other immunoassay kits; the wording in Notification No. 13/95-Cus. is consistent with Notification No. 208/81-Cus., and typographical variations in private publications do not change the scope of exemption, so pending cases should be disposed accordingly.