10/22® Magazine Dust Cap-fits JÄGER 22-25W?? and Ruger® BX-25® Magazines-BLACK. Made from durable NBR (Nitrile Rubber), our dust caps exhibit high tensile strength, as well as excellent abrasion, tear, and compression set resistance in temperature conditions ranging from well below 0 degrees Farenheit to those in excess of 200. Our rubber caps help protect the rounds in your magazine against dust, excessive water and other exterior contaminants.