Ted wrote:
I bought a Task Force a year or so ago and am quite disappointed as it
flickers so much. Even not on the bike it is only on half of the
time. I have stuffed tin foil against the battery contacts. It will
flicker bright and dim or on and off. Not very useful on my bike.
Jiggling or slapping it seems to change the light; that is if it is
bright that might make it dim or if it is dim or off that will make it
brighter.

Anyone else with this problem? Does the Costco one act the same way?

Ted.

That's always a possible flaw in using a flashlight for a bike light --
they may not handle the vibration well. It's worse with the new
"multi-mode" ones because when the current is interrupted, rather than
just flicker, they switch modes. I have one that does that, but only
with a particular set of batteries, so I haven't bothered to mess with
it. I think part of the problem is different battery chemistries and/or
makes aren't quite the same dimensionally, causing some to have too
loose a fit. It could be some other contact, or even the switch. I'm not
sure aluminum always has a reliable contact resistance.