Very cost effective - LANTAC S-KIT Upgrade Glock 17/19 Gen1-4 Spring Kit

If you have a Gen 1 - 4 Glock or clone, This is just about the best way to get a good trigger. If you have a Gen 5, two of these are very useful. Add
either a "Dot" or "Minus" connector and you've got a great trigger pull. You can go around the world searching for Mr. Goodbar but for the money, this kit is very hard to beat.