Well the dimensions are 7" long x 9" tall x 3 1/2" wide. What you need for the internal baffles are 1 piece for the reaction chamber thats 4 1/2" inches tall to contain the bubbles but if i was to do it again i would also put another piece the same size in front of the pipe to channel the bubbles more efficiently to the collection cup. Im surprised cpr hasnt done it yet but i see many flaws in their designs, but they're just lazy. Anyway the pipe cuts are 3 1/2 on both sides but make sure the outlet side pipe is larger than the intake. I used 1/2" for the intake. so larger than that on the output probably 3/4". All the elbows are 1/2" pvc
(good ol home depot) i bought a 10 ft piece of 1/2" tube for i think 1$. The intake hole is cut just over 1/2" i measured it but making it slightly larger than the threaded pvc
connection. The guy said it was just larger than 3/4" when we drilled it out. The collection cup is from tap plastics. its a 3 1/2" box and the funnel inside is just something i designed its from acrylic pipe and a scotch tape holder inverted thats the only ghetto part of it all. The other internal baffle is 7 1/2" x 3 1/2" before the outtake pipe. I used an airstone because the powerhead i was working with has a very crappy venturi and it wasnt until later i decided to do spray injection.