Those pipes are 12" long 1/2" pipe nipples each has 4 1/4" holes cross drilled in it. 3 have pipe caps on them on 1 has a ball valve. Seems to work very well. In fact it may work too well. I am having trouble getting grill temps below 300. If i measure near the edge of the barrel I read 225-250 but over 300 right in the middle below the grill. The pipes fit very tight in the holes i drilled but i am going to try silicone around the holes to see if i am getting air leakage there. It may not be a big deal either way because it still makes great Q.
UDS, Gourmet ECB, and an Arduino Powered Controller.