This is a Glock Sight, model 39928.
GLOCK night sights are equipped with contrasting tritium inserts" enabling simple" accurate and quick target alignment in all light conditions.
Features:
Front fits all models
Rear size 6.5mm
Fits all models except G42/G43
Standard height on G17 G19 G22 G23 G26 G27 G33 G34 G35 G37 G38 G39 (Including Gen4).
