The DL flyer
A DL flyer is a single flat sheet, 99 × 210 mm — the same width you'd get folding an A4 into three, but here as one unfolded piece.
Trim size99 × 210 mm
FormatFlat, no fold
Comes from⅓ of an A4
FilesLayered PSD, smart objects
It's the size built around the envelope and the rack: it slides into a standard DL envelope without folding, and stands in the brochure holders you see in hotels, clinics and reception desks. That makes it the natural pick for a mailer, a rack card, a price list or a flyer that has to look tidy sitting in a slot rather than handed over in a pile.
The shape decides the layout more than most formats do. It's narrow and tall, so you're working a single vertical column — no room for two columns or a wide image, and a header that fills the top leaves everything under it fighting for a strip. It reads top to bottom in one line, which is why the good ones keep one clear message rather than trying to be a poster.
In the sets: flat from above, held in a hand, pinned to a board and stacked, so you can present it clean or sit it in a real scene. Each is a layered PSD with smart objects — the artwork sits on its own layer, so replacing it leaves the lighting and shadow untouched.