Thanks, Dan. That sounds like it. I only learned of it AFTER I'd tossed my first one... drat. My second one continues to function correctly.
Brf is correct. To function, the Zerostat's trigger must be pulled s-l-o-w-l-y.
Brf is correct. To function, the Zerostat's trigger must be pulled s-l-o-w-l-y.