This tape is made from Sunbrella fabric. The tapes lengthwise edges have been turned under for a finished look (i.e. hemmed edges).
Facing is used to trim and reinforce edges. It can be sewn flat along the edge to be covered or it can be folded over the edge and sewn down. It is often used to face both sides of a window panel or to reinforce a sleeve for zippers. Note: one lengthwise edge is turned under 1" and the other 1/2". The 1" fold is wide enough to provide an appropriate additional layer for fastener installation.
Sailrite stocks a 2" Binder Attachment that folds this facing and feeds it through a sewing machine perfectly!