Full flight a-arms 300ex

I just got another 300ex the other day and was told it has +3 +1 full flight a arms. Iv never had aftermarket a arms can someone explain what the numbers mean? Also the rear end is stock. What do I need to do to equal out the width in the rear to match the front? Thanks everyone it’s been awhile since iv been on here!

Attachment 25264

Full flight a-arms 300ex

I just got another 300ex the other day and was told it has +3 +1 full flight a arms. Iv never had aftermarket a arms can someone explain what the numbers mean? Also the rear end is stock. What do I need to do to equal out the width in the rear to match the front? Thanks everyone it’s been awhile since iv been on here!

Attachment 25264