Summary: This simple attachment makes it much easier to get clear closeup pictures underwater (on land, too). You need to follow the directions for success. For example, when using it underwater. it should be mounted on the camera while submerged to allow an incompressible layer of water between the two lenses. It's a little tricky getting it on and off with thick cold water mitts (like we use up here in New England), but I got the hang of it. Nice product!
Summary: to attach a string from the wide-angle lense to the camera. Due to the lense blocking out the flash you will need to take the lense off frequently in order to take flash pictures. If you don't attach it to the camera it is fairly easy to re-mount it incorrectly and have it fall off. Fortunately someone else on my dive found mine and returned it.