Flatsys had long hair, which went to the floor, generally in vivid colors (like bright blue, bright yellow, pink, etc.). They were made of soft vinyl with wires inside the limbs, neck, and body which made them posable. They wore mod clothes reflecting the styles of the 1960's. Their faces had sweet, grinning expressions with eyes looking either to the left or to the right. Each Flatsy had a theme and came with an accessory and a cardboard liner with a picture in keeping with that theme. They also had a plastic clip to hold the doll in place on the liner card which also detached for play time. Every Flatsy came with shoes and in nearly every case, a hat.
Flatsys were made in three sizes: Mini, which are about 2-1/2 inches tall; Medium, which are about 5 inches tall; and Fashion, which are about 8½ inches tall. The Minis and Mediums are very similar in appearance, except of course for size, while the Fashions are very tall, thin, and have rooted eyelashes.