For those of you who didn't know, like me, a 1:1 barrel valve (k-style) is 7" long with fittings and 3.25" high. The main line is a #8 size and the return lines are #6 which is basically 1/2" according to the guy on the phone at Enderle. I'm going to attempt to make one. Ted's modeling has good info on making one, too. Those of you who are good at making them, please add your wisdom.