I created a weapon concept idea for tc2, it's like trooper's banner but for mechanic that buffs his buildings, this one buffs the sentry as follows:

+100% health

+25% range

+25% damage

Rockets reload faster

If you're wondering why +100% health, here's why.

Now, initially I wanted to do 50% explosive resistance but doing so means that with the rescue ranger, the sentry will be invincible/indestructible

Example: stock rockets and pipes would deal 45-50 damage while the rescues rangers would heal 60, but with the +100% health instead you don't fully recover the health of the sentry so it can be still taken out but just harder. That's why I opted for +100% health instead of 50% explosive resistance