Rubber is a Rare natural-type fruit in Blox Fruits. It is a inexpensive and simple to obtain Rubber fruit. It costs $750,000, or 1200 Robux, and has a 13% chance of being in stock, so you can get it any time. It has a spawning chance of 7%, so there is a high chance that you will find it while playing.
Rubber is a pretty bad fruit when you compare it to other fruits, but there are a few places where it is extremely good and worth using. The first place where you can use Rubber is when you are doing raids because it will provide you with a lot of immunity. One more place where Rubber is good is for farming sea beasts. When it comes to PVP and other PVE content, it does not perform that well. So if you are a new player who does not use this fruit, there are better options for you.
What combo you will use depends on your in-game situation, who you are fighting with, and what you want to achieve. It is best to spend some time testing all possible combos, and by doing that, you will learn how to use what works best for you and also how to counter it. So go and test Rubber in a game.