These are iron sights for the Decker 380 from the Black Lotus Coalition. Use if you have configured your Decker with picatinny rails (including the rear picatinny rail adapter). They are designed so that they rise just above the bolt charging handle, and also gives you another rear rail for attaching whatever rear accessory you want.
Update: Version R2 - I noticed that the old rear sight block made it impossible to remove the dust cover. This is now fixed. Also I've separated the rear rail clamp into two pieces to make it much easier to install.
FRT-15 Trigger system