This is a new old stock component, original Commodore spare part number 318069-11. This chip can only be used in A500+ boards or special 2M chip ram expansions. Starts in NTSC mode, but can be switched to PAL in software.
Exchanging the Agnus chip is a technician's job. You should only buy this chip if you have some experience exchanging chips in your Amiga. Delivery in anti-static packing.