Aquarium Pharmaceuticals Rena Air Repair Kit 300 / 400 includes the diaphragm and valve block for the 300/400. These parts are the most likely to wear out during normal use. These parts will fix problems with air output and/or increased noise. The diameter of the outside rubber is approximately 1 1/2".
Aquarium Pharmaceuticals Rena Air Tune-Up Kit 100 and 200 includes the diaphragm and valve block for the 100/200. These parts are the most likely to wear out during normal use. These parts will fix problems with air output and/or increased noise.