Stradlin's next iTunes release, "Concrete", came out in July 2008. In addition to his regular collaborators, Stradlin also invited Duff McKagan to play bass on three songs, including the title track. Stradlin then released two more albums through iTunes: "Smoke", which came out in December 2009, and "Wave of Heat", which followed in July 2010 and again featured McKagan, who appears on seven tracks. Also in 2010, Stradlin appeared as a guest on Slash's first solo album, "Slash"; he performs rhythm guitar on the first track, "Ghost".