Which Magsafe 85W for MacBook Pro Mid 2012

I need to replace my Magsafe power adapter, but looking online there seem to be 2 different ones for MacBook Pro Mid 2012. One is a Magsafe, the other is a Magsafe 2. Also does it make any difference whether the connector is T shape or L shape? And finally!......The part number on mine is A1424. Does it have to be this same part number for a replacement? I've seen one been sold on eBay for a good price, but it's a Magsafe 1, A1172.

It's so confusing!!! :)