Before the popularity of mobile phones, phone cards were a big deal. These plastic cards had phone minutes on them...and when you used up all the time, you could collect the card much like a sports-card. (only they are made of plastic) Quite a few Sonic theme cards were produced, and these yellow & red cards are rather old. There are numbers across the top, and an arrow showing how to slide it into a phone. The yellow one says 'Mega Drive' below the Sega logo, while the other is the title screen art from Sonic 1.