MDRX, AR15/5.56 type mags adapter kit.
 
Convert your MDRX 7.62 mag well to fit 5.56/AR15, compatible with most standard AEG Ar15 mags.
 
The kit is coming with :
Mag well adapter (PA6 nylon material)
4 pairs of spacers to adjust the magazine wobble depending on its thickness (PA6 nylon material)
5.56 type mag catch (6061 aluminium)