a metal chamber pipe (the bud from my old one would get so rezy and it acted like a filter so every hit was so smooth i could take the biggest hit i possibley could, hold it in for 1min+ and not cough.) ive been meaning to buy a new one but no headshops around me.
Knife hits rock my world the most and I think it's hands down the way to go the farthest out of a little bit of weed, but as for smoking from knife hits everyday I like my lungs and nasal cavity too much.