vaeevictiss
A RDIAS ( registered Drop in Auto Sear ) will allow the gun to function as any normal M16 would. Rather then having the extra hole drilled into the lower to allow the use of auto trip such as anormal M16 or a Registered Receiver full auto AR15 will have, the RDIAS is a drop in unit that preforms the same task.
They function well and allow select fire.
refferance info:
http://www.quarterbore.com/nfa/dias.html