Flyers are what we typically refer to as color copies, though it usually refers to a one-page (or two if double-sided) document intended specifically for promotional purposes, such as products, services and events.
It's recommended you use at least th 24/60# laser white smooth stock, particularly if you're printing double sided. The 20/50# is acceptable but it is fairly thin and can show through to the backside if there's a lot of toner coverage.
|Half Letter (8.5x5.5)||JPG||PSD||PUB|
|Half Vertical (4.25x11)||JPG||PSD||PUB|
|Quarter Letter (4.25x5.5)||JPG||PSD||PUB|
|Third Letter (3.67x8.5)||JPG||PSD||PUB|