The tools and materials needed to tighten the chain on your Ryobi pole saw are similar to those necessary for any other power tool, with a few notable exceptions. Rather than just one or two wrenches, you will likely require both an adjustable wrench and large channel locks in order to get sufficient torque on many bolts. The most difficult part of replacing the chain is removing the blade assembly; you might even consider purchasing another saw just for this process if it proves too difficult otherwise.