Precision, compatibility, and safety are the cornerstone features of the ASP D1 Inert Test Inserts. These proprietary inserts, intended for ASP Metro D1 Defenders and Sport D1 Defenders, are crafted from high-quality aerospace aluminum and solid brass. Each insert houses a specially produced valve system and patented dispensing mechanism, providing around six half-second bursts. One of the distinct advantages of this setup is its facilitation of safe training - using our Test Inserts that contain a harmless, inert aerosol. It's highly recommended to practice with the ASP Defender using these inert inserts before outfitting it with the active D1 Insert.