The Captain America #1 Variant cover was only given to stores who bought 100 copies of the regular issue. Meaning, they had to order 100 of the regular issue in order to get 1 variant. This makes this a very rare item. This copy has been signed by Neal Adams and authenticated by CGC as a Signature Series, making it even rarer. I don't think I have seen a signature series of this comic at all, anywhere.