The WWSD2021 lower includes all the parts going into the lower of the WWSD2020 Rifle with the addition of the RTS-1 Rekluse trigger. The Rekluse is the next evolution of the patented Sear Link Technology trigger series by KE Arms. The Rekluse is even more sealed against dirt and debris and features a full power hammer spring making it more reliable with hard combloc primers and bolt carrier groups that have firing pin safeties. KP-15 Monolithic Polymer Receiver KE Arms Rekluse (New SLT Variant Trigger) KE Arms Ambi 90/45 Wedge Selector KE Arms Ambi Magazine Release PDQ Lever Installed with Receiver Milled to Accommodate it JP Silent Captu Mfg: Ke Arms