Damage Industries Enhanced Spring, Recoil Buffer (Carbine and Rifle)

The carbine length springs come in plastic bags that are heat-sealed at one end

I purchased these four springs from Damage Industries LLC last year (today being 1/9/2014) during one of their Deals of the Week sales. They are made from chrome-silicone and sports a black oxide finish. Each spring is estimated to last more that 750,000 rounds a piece, according to their website and a video on YouTube, titled "AR-15 Buffer Springs - More than you need to know". That's probably more than I'll ever shoot in two years (most likely held back because of a lack of money and time, not lack of desire).

The rifle-length springs a shipped using an older method: paper wrapping.
Personally I think it looks pretty sweet.

I bought these springs when I was still making up my mind about whether I was going to build a full-sized rifle or a carbine, which is why I have two rifle-length springs and two-carbine length springs. As you may have guessed from the receiver extension/buffer tube I chose, I am building a carbine. I will be doing my best to purchase a lower receiver and tools to put everything together.