This was designed specifically for the AirFit F20 and the AirTouch F20 and the AirFit F30. It is not designed to be used on any other masks. This strap is designed to add stability to the mask and prevent leaks. The strap attaches to the mask over the hose connection and then wraps around your head and connects with velcro on the side. There are 2 pieces of velcro at one end, you can cut between these to shorten the strap if necessary. There is a black strip covering over a central piece of velcro that you can remove if you want to attach it to your headgear. You can do a quick test to see if this will strap will help with your particular leak: First, loosen the straps until the mask leaks With the palm of your hand against the hose connection of the mask, press the mask toward your face. If that stops the leaks, then it will help. It is a bit much to add another strap around your head, but it does work well if that is your main issue. The installation instructions are included in the package. Do not use on a mask where it may cover the vent holes near the hose connection. The Anti-Leak Strap AirFit F20 is for the following masks only: ResMed AirFit F20 ResMed AirTouch F20 ResMed AirFit F30 For best results, hand wash in warm soapy water and rinse well. Wash weekly or more often if desired. You can use any type of soap you would use on your skin to wash this product. If you machine wash and dry, use delicate settings and a cooler dryer. Any pink micro fiber products should be washed before first use to remove excess dye in the fabric or it may turn your mask pink (that does not hurt the mask)