Plaintiff appeals from the March 26, 1985 judgment of the Tax Court upholding the assessment by defendant of sales tax on two activities of plaintiff fully described in a stipulation of facts filed below. The first activity, held taxable pursuant to N.J.S.A. 54:32B-3(a), involved printing materials in New Jersey for out-of-state customers, putting them in envelopes, addressing them as requested by the customers, and mailing them at a U.S. Post Office in New Jersey for delivery to addresses outside New Jersey. The second activity, held taxable pursuant to N.J.S.A. 54:32B-3(b)(5), involved purchasing of advertising materials by plaintiff instead of printing them and then handling same as in the case of the printed materials. We are *323completely satisfied with the determination of the Tax Court and therefore affirm substantially for the reasons expressed by Judge Richard M. Conley in his opinion, reported at 7 N.J.Tax 23 (Tax Ct. 1984). We add simply that although there can be no equitable estoppel against defendant under the facts of this case (see Airwork Ser. Div., etc. v. Director, Div. of Taxation, 97 N.J. 290, 478 A.2d 729 (1984)), we are in full agreement with Judge Conley’s further determination (from which defendant has not cross-appealed) to vacate the previously imposed penalty and reduce interest to the minimum statutory rate.

Affirmed.