mufflers on cylinders??

i am ordering my air cylinders for my car tom. i am running 3/8 air line. so do i need to order 3/8 mufflers or 1/2 mufflers from gauge store??? and as in mufflers i dont mean to slow my cylinders down i mean to keep the road grim out of them.. does anyone know.. all help is greatly appreciated,

inaweekillbdrgn