ive seen them made from drilling a hole in a large coffee can and tying a thick shoe string in the hole and letting it hang and you put your pointer and thumb at the base of the can around the string and pull down i guess its like the old paper cup phone idea it vibrates the string and echoes out of the coffee can
yeh ,when i bought this call it came with the tape but it still takes alot of practice to make it sound right. i should take the tape in the woods and play the back end of it but they don,t alow that up here in maine.