This is a replacement battery pack for the Medela Pump in Style breast milk pumps. It holds 4 double A batteries on each side for a total of eight batteries. These are easily lost so it's good to have a backup ready to go.
The Medela part number is 9017002. You might also see these numbers on the battery box: #901.7002A 1997342 A 1001
This item is only for use with the Medela Pump in Style #57000 & #55000 series breast pumps. To prevent battery leakage and damage to the unit during shipping, batteries are not included.