The boon fly is compatible with the boon lawn and boon grass countertop drying racks it is designed to provide extra space to dry small sippy cup and bottle parts above the main drying rack leaving you more space to dry large items the stem is tall enough to hang bibs on and is interchangable with the boon stem sold separately all materials are bpa pvc and phthalate free and is safe for the top rack of a dishwasher