The VIPER series suppressors have been specifically engineered to mount securely on the unmodified M10 and M11 Ingram submachine gun barrels. Gemtech's patent-pending mounting system prevents unintentional loosening or unscrewing during use, even if the user does not hold the suppressor. Initial installation is simple, and subsequent installation and removal simply involves sliding the suppressor handguard forward to disengage the locking mechanism. The VIPER retains the classic cosmetics of the Sionics-type suppressor in a modern design. Although significantly smaller than the Sionics design, the Viper significantly outperforms the original by more than 10 dB. Three versions of the VIPER are available: The VIPER-9 for the M10 and M11 9mm submachine guns and the VIPER-380 designed specifically for the M11/M12 .380 Ingram submachine guns.The full size VIPER-45 designed specifically for the MAC M10 weapon in the popular .45ACP cartridge is scheduled for production in March 2002. These units have no adverse effect on either the handling or accuracy of the weapon. No wipes or mesh packings are used.