"DIXI" sentry is a special Engineer build that allows to build sentries that deal big damage with low amount of money.
It's achieved by equiping primary weapon like the Rescue Ranger and upgrading two things:
1) sentry damage in PDA settings
2) sentry damage multiplier in Primary weapon tweaks
The player can get as much sentry damage and sentry damage multiplier as he wants, because after buying the special tweak, he can remove the downgrade from the tweak increasing sentry damage multiplier.
The build itself is about multiplying sentry damage by sentry damage multiplier (obviously), so you can deal big damage in early stages of game.
With the rest of your money, it's recommended to buy sentry health, range and deploy time decrease.
That way, you have sentry with big range, dealing big damage and building really fast. For small amount of money.
Some players call it "DIXI" sentry by the name of the player DIXI who has been using it for a long time.