These coupons were included with various sets throughout the 70's. They advertised products like the "Aqua-Leash" and the very rare "Instant Aquarium". The coupons themselves are a rarity, as they were either thrown away or sent in. An interesting thing to note is that these coupons once replaced the eyedropper included in many larger kits. In fact, they were rolled up and placed in the same blisterpack.
In some kits, the dropper was replaced with coupons.