I recently got a 4x4 electric chainsaw in the woods. Accidentally and unknowingly bought a normal tire and chain oil. Wow that was a mistake. It smelled so bad, like a highly toxic chemical oil smell, that I couldn't even get rid of it, let alone take it with me in my new jeep. Then I found this Bio Pro and I can tell you that I am sensitive to chemicals and such, but Bio Pro has almost no smell. Reminds me of unscented dishwashing liquid. And it works perfectly. I'm just buying another bottle to have an extra one.