Digital Antenna

My cousin asked me a favor if i could buy him the digital antenna for him. I had no idea about it and he told me where to buy it because he can't find the right one back where he's at. He said he will send me some money for it so i can get it right away because he needs it as soon as possible. Really, i don't really know what it's for, my cousin will tell me later what he will do with it. It sounds interesting to me but i never heard of it until he mentioned it to me.