Batting tape is a knit tape with bonding on the back. It is about 2 inches wide. Mine is made by Pellon. You lay it over the joinings of the batting, and just touch the tip of your iron to it to glue it to the batting. If you do this enough it is like basting so doesn't mash the batting. Just quilt right over it andyou can't tell where it was pieced. I used this just recently for the first time, and it is sure faster than hand sewing or even zig zag with the machine.