The wedge is placed at the bottom (muzzle end) of the holster, next to the body. This helps tip the rear sights back in to your body. It’s most useful when appendix carrying, but can be used at virtually any position.
Two different wedges are available. This one is the universal foam wedge, which comes with the velcro needed to apply it to your holster. The RCS rubber wedge is available, but to avoid confusion it’s no longer selectable under this product.
The closed cell foam wedge is ambidextrous and will work on most holsters, excluding the minimalist styles that don’t fully cover the slide. It is more comfortable than the RCS model, but will not last as long. Attaching with the supplied velcro is simple, just clean the surface of your holster well and attach the soft side to it. If it’s too large, it’s easy to trim down with a sharp knife.