When speed is what you need to, like when you need to get that flag capped or to outrun a tank that's chasing after you, a speed boost would be a heaven sent!
The speed boost in Tanki X will bump up your tank's movement speed by 30% for 45 seconds via nitrogen oxide (also known as "Nitro" in car racing games). Your tank's turret maximum rotation speed will also be increased, giving you that extra millisecond to get in the first hit.
Although you can picked up the speed boost drop boxes for free in specific locations in the game, you can also purchase extras and have them deployed into the battlefield using diamonds. Of course, you'll need to be careful where exactly you deploy your "care package" just so you won't accidentally giveaway something you've bought to a teammate who simply happened to be passing by, or worst, the enemy tank you're trying to outrun and escape from.