The famous Eagle "doohickey" aka balancer adjustment lever. Machined from solid 17-4ph stainless steel that was heat treated to H900 condition. This is the strongest and best doohickey you can buy. There are copies, but none are as good. Eagle has hade small improvements since the first one was machined in the early 2000's.
Now includes the torsion spring. This is absolutely the best setup for adjusting your counterbalancer system in the KLR650 engine. The torsion spring has these features that the extension spring doesn't:
Captured on install
Takes the slack from the system in the best way
Does not constantly stretch and relax while the engine is running
Longer adjustment arc compared to extension spring setup.