The Daniel Defense rail interface system (RIS II) was designed at the request of the United States Special Operations Command (SOCOM) for the SOPMOD II program. SOCOM had a specific requirement for a free float M203 solution and Daniel Defense responded, designing a revolutionary product to meet the government's need. The Daniel Defense RIS II allows the individual operator to free float the M203 grenade launcher without additional parts. As important, special tools are not required to mount the M203 grenade launcher. This was accomplished by integrating all of the needed parts to free float the M203 into the rail itself. The Daniel Defense RIS II is to be used in conjunction with the MK12 low profile gas block.Features:Free-floating barrel design for increased accuracy2-piece design for USSOCOM allows for the attachment of an M203 grenade launcher when lower rail section is removedBattle - tested, 6-bolt bolt - up system securely attaches handguard to the upper receiverGrade 8 military specification fastenersUninterrupted upper rail platform and Mil-Spec 1913 Picatinny railsSteel barrel nutCarbine gas system