That is part in an early version of Ramsey's R.I.P.
You jam it into the front leaf springs of a Quigley or SMB 4x4 conversion. It smooth's out the ride and gives you added lift at the same time. The handle allows for easy installation and is also a place to attach the travel limiting strap to keep you from "over articulation."
2005 5.4L E250 RB50 4x4 SMB
2000 4Runner Limited 4WD
But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Romans 5:8