The breast pump adapter that is included with our Breastmilk Bottle, Starter Set, Newborn Set, Complete Set, and Ultimate Set is compatible with most standard size neck pumps (for example: Medela or Ameda). If you have a wide neck pump (e.g. Spectra), we have a Breast Pump Adapter Set, sold separately.Note that most wearable pumps (e.g. Elvie) use built-in containers and cannot pump directly into our bottles or storage bags. However, you can transfer any expressed milk from the pump into our bottles or storage bags for convenient, stackable storage.