This is the 9017002 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.
The Medela part number is 9017002. These numbers: #901.7002A 1997342 A 1001 are also on the battery box.
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.