The SPC 23194 is the correct Camber/Caster Cam/Sleeve for your Explorer which has a Dana 35 front axle.
You can rotate it to give you from -2.75 to + 2.75 degrees of change. If you have no idea what size you need I would buy the SPC 23194 as it will give you the most adjustment. I have heard of other Cams/Shims that can get you more but I have not found them. Remember, you get less adjustment when you use the Cam/Shim on a 4x4 compared to a 4x2. The SPC 23194 gives you 3.5 degrees of adjustment on a 2wd and 2.75 on a 4x4.
At 4:40 on this video:
http://www.youtube.com/watch?v=In31H0iBipQ&feature=player_embedded you see them removing and installing a cam/sleeve on an Explorer. I have never needed to use the special tool to pull the cam/sleeve. I have used an air chisel and a pry bar before.
~Mark