This is the military model so you will need to remove the delta ring. this is also the long rail version that extend pass your front sight base, you will also have to remove the front handguard cap.
this unit is like new with the longer optional #4 rail on the bottom. the plastic lower handguard has a very minor ding on it. it will come with all the accessories that was shipped with the handguard.
I am asking 300.00 for the SIR.