This is the Rolleiflex battery for Hy6 and Hy6 Mod 2 cameras with the standard contacts in the grip arm battery compartment.
These batteries are supplied directly from DHW and are not aftermarket.
Note: You can find aftermarket batteries on Amazon and Ebay and other places if you look for Sony N 550 compatible batteries.
Note: Some Rolleiflex Hy6 and Hy6 Mod2 cameras were fitted with the Leaf Aptus style battery contacts such that users of Leaf AFi digital backs could keep a single battery type and charger instead of two sets. All the AFi camera bodies will have the Leaf battery contacts. This is not the correct battery for those cameras.