Someone asked about arm warmers in white. That didn’t sound good to me since white will soon be dingy grey. But what she wanted to know was how to have your arm show up when making a turn signal. Good question. Here’s one answer-Corrie
Brent in San Francisco sells nifty reflective bike safety stuff through his Bike Wrappers business.
His cycling arm warmers have 16 inches of reflective material, much more than the tiny logos on your typical arm warmers.