400ex rims for sale

[xX-400racer-Xx]

up for sale is a set of itp offset steel wheels. they are baerly used and aren't bent. they are 4-1 offset. so they widen it by 2". they are $35 shipped and if you want pics e-mail me at slimjim760@yahoo.com

Could you send me pics? my email is silver_fox_000@hotmail.com.
What does it mean offset? Are they front or back rims or both? Do they widen the entire machine or something else? I'm not very familiar with them lol. What are the advantages and disadvantages of offset rims? Thanks. Im very interested.