What does Luffy use when fighting?

Answer 1

Eating the Gum-Gum Fruit(also called Gomu Gomu fruit) gave his whole body the properties of rubber, which makes him virtually immune to all blunt force attacks (including the round flintlock bullets used in the One Piece universe). The fruit also gave him the ability to stretch at will. Combined with the elasticity of his body, he uses that ability to accelerate parts or the whole of his body as if shot by a slingshot to deliver punches, kicks, headbutts, body checks, or simply for propulsion. But like everyone who consumed a Devil Fruit, Luffy is unable to swim and when drenched in sea-water or in contact with an artifact blessed by the sea quickly loses his strength. He also has great physical strength as he was able to knock over 2 large apartment buildings at the same time (Water 7 arc).

As one of the top fighters of the Straw Hats, Monkey D. Luffy has extraordinarily inhuman strength, enough to break through stone and shatter steel with his bare hands, and can move at extreme speeds, eventually catching up to even the speed of weaker CP9 agents without the use of his Gears. Luffy's sheer physical strength and dexterity is a result of his grandfather's unorthodox training methods and he claimed he had a punch as powerful as a pistol even at seven years of age.

Unlike Zoro or Sanji, Luffy's fighting style is freestyle and improvised; it follows no particular code of honor, and so if necessary he will attack women or animals, hit below the belt, attack even if enemies have their backs turned on him or are otherwise unprepared or unsuspecting, use enemies as human shields or even bite his opponents. While fighting, Luffy can also think on the spot, and come up with creative counterattacks against his enemies. This however leads both enemies and allies alike to wonder if Luffy is taking the fight seriously, especially when he comes up with ridiculous moves (like Crocodile when Luffy became Mizu Luffy), which prompts Luffy to respond that he's always serious. He also appears to be intelligent enough to at least understand fundamental concepts, such as rubber being a natural insulator, which might be why he did not bother ducking out of the way of Enel's lightning attacks as it would have been pointless to do so since he is immune to such attacks.

Answer 2

i have eaten the gomu-gomu no mi and have the capabilities of being able to stretch, you can look me up on my attacks on Google