You can use any newer Echo 18v battery. The clutch mechanism makes it incredibly safe. I found the starting instructions superfluous. It does not include it, and don't expect it to. You must use Motor oil, not chain oil.
The fact is that the Echo CS-590-20 was the Echo Saws that we graded most highly. That doesn't mean there aren't several other really great alternatives when it comes to Echo Saws. We have a breakdown of them here.
Next on our list is manufactured by Echo which is a very trusted tool brand. Echo's Chainsaws are among their top products. It was great to try the CS-400-18. I was very pleased with this tool!
The model CS-400-18 Chainsaw by Echo, at $294.99 is a particularly great Saw for the money. The Echo CS-400-18 is really a solid alternative. Of you are unsure about our top choice, I'd advise to select this Saw.
Full Echo CS-400-18 Review