The base of this gun is a Magpul LM4. The lower and upper of the gun are discontinued models now, as well as the Magpul select fire switch. On the back is a Magpul CTR stock and a custom modified barrel tube to fit a Noveske rear sling mount on a Magpul sling attack point. The top of the gun features flip up MP7 sights or you can keep them down if you choose, as well as an EoTech 553 replica. Where the ris meets the upper is where we see the rarity of the gun. BoobieGBB on YouTube custom made this LM4 RIS to fit a custom length inner barrel set up, also having to create a custom barrel nut to hold the entire set in place. The end of the RIS is threaded and a fat striker type flash hider is attacked straight to the RIS itself to minimize touching the inner barrel. Under it is an MFT forward grip with 2 spots for pressure switches. All together with the custom mods done, the discontinued parts, and the fact that there are only 3 in the world, the collector value for the price is very high, as well as the fact that it still shoots like a tank and comes with 4 31 round gas mags. I am open to trades. My field is an outdoor so I'm looking for things along the line of upgraded M4 DMR's, Krytak SPR, etc. Instagram: @regularguyairsoft to see more on the gun YouTube link to see the actual gun from the creator : https://youtu.be/NvvNCKmZqH0