What is the difference between the 661-5229 and the 661-5557 batteries for the Apple MacBook Pro "Core 2 Duo" 2.4 13" Mid-2010 A1278 EMC 2351?

Apple 60W MagSafe 2 Power Adapter
(MacBook Pro with 13-inch Retina display)

Apple 60W MagSafe 2 Power Adapter (MacBook Pro with 13-inch Retina display)

Product No Longer Available

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