The black part is the piece. This is a small adapter cylinder with the proper sized holes for the bottom piece and the adapter hose piece.

I put this together because the mini-pump I had for the FoodSaver bags stopped working. But I had a perfectly good larger pump as part of the FoodSaver sealer.

This adapter allowed me to re-use the nice rubbery bottom part of the mini-pump to get a good seal with the bag for suction.

They do sell these sorts of thing, like this (https://www.amazon.com/Accessory-Compatible-FoodSaver-%EF%BC%8CCompatible-FM2000%EF%BC%8CFA2000%EF%BC%8C/dp/B0BVZP8CX4/), but I already had the pieces and this was cheaper.

For context, here is are the pieces I'm referencing:

• Minipump: https://www.amazon.com/FoodSaver-31161370-Cordless-Handheld-Vacuum/dp/B07VSVRNFH/
• Main food-saver with accessory port: https://www.amazon.com/FoodSaver-FM2100-Manual-Sealing-Preservation/dp/B00LUGK5QW/
• Adapter: https://www.amazon.com/FoodSaver-Accessory-Vacuum-Sealers-Clear/dp/B00T699C14/