Nest Wall Diffuser Refill - Birchwood PineEnhance A Room with Our Nest Wall Diffuser Refills! Simply insert one refill into your NEST New York Wall Diffuser (sold separately), to enjoy approximately 30 days of uninterrupted fragrance. Scent your world with this exquisitely fragranced Wall Diffuser Refill Duo featuring a bestselling blend of white pine, fir balsam, and birchwood over a base of rich musk and amber for the aroma of a majestic winter forest. The Nest Wall Diffuser Refill Assorted