From Monte Design:
The Rockwell bassinet features foam sides. Breathable sides are not a safety requirement and there is no evidence that breathable sides make a safer bassinet. The primary safety concern with any bassinet or crib is the use of toys or blankets when your infant is less than 1 years old. SIDS (sudden infant death syndrome) is a safety concern for all new parents and any company claiming that breathable sides reduces the risk of SIDS would be in violation of the Federal Food, Drug, and Cosmetic Act (U.S.A). The FDA has never approved a product to reduce the risk of SIDS.