内罗纹管 ribbed tube

罗纹支管台 threadolet

管罗纹 gas thread ; pipe thread

罗纹烟管 spirally corrugated tube

锥管罗纹 taper pipe thread

直管罗纹 straight pipe thread

锥管罗纹弥缝焊毗连 seal-welded taper pipe threaded joint

带罗纹的钢导线管 Screwed Steel Donduit