Glock Gen 5 Safety Plunger.
 
Made with heat treated medical grade stainless.  Machined out of solid bar stock.  Held to aerospace tolerances.
 
This aftermarket safety plunger, has a mirror smooth finish where the trigger bar passes across.  The part that Glock uses, is made with "metal injection molding" or "mim."  In effect it is a casting.  And has surface finishes like a casting.  Replacing your oem plunger with our machined from bar stock plunger will improve the trigger pull on your Glock.
 
My personal Glock 17 has over 12,000 rounds thru it.  And it barely shows any wear.  The 4th picture is of that "used" plunger.