i have some Xs sights for a glock 21 that i won at a 3 gun match a couple years ago, taken out of the package never used.

the tritium still glows fine the package says for 20/21/30/37/39 (if you need me to check again on models let me know)

this is the smaller dot (not the "big dot") and the bar rear

$50

I also have the XS sights tritium front and non tritium aperture rear for a 20 in barrel (stadard length barrel M1A)

they were mounted, (I had to slightly file the front to fit the M1A front sight assy dove tail), zeroed, and removed the same day when I realized I needed scout length barrel sights. They should be fine for a standard GI length barrel.

I used this configuraqtion on a scout/squad barrel and prefer the tritium verticle bar on the front sight over the tritium dot. In my opinion the tritium bar front is a better sight for precision work and is still viable for CQB.I

$60