The Victor Precision +5 magazine extension base pad for the Magpul PMAG magazines is CNC machined from Actel, a hard engineering, lightweight plastic with high tensile strength and rigidity. The .223/5.56 has a total weight of just 28g, this extension and will allow you to add an extra 5 rounds to your Magpul AR/M4 PMAGS. Just remove your current base pad & plate and fit the extension base pad onto your magazine. The .308/7.62 has a total weight of 20g Just remove your current base pad & slide the extension base pad onto your magazine. This extension will not spring bind on 20 or 25 round magazines. Please check your state's regulations as to whether you're permitted to use these. Compatible with Gen 2 & 3 magazines in .223/5.56 x 45  and .308/7.62. Manufactured in Queensland - proudly Australian made.