A quick tutorial on Octura props. The "X" series are non-lifting props. The first number will give you the pitch in millimeters times the diameter. If it's a 4, then the pitch is 1.4 times the diameter.
A lifting prop wil use 2 first numbers like a 14 which is the same as the 4 but just designates it as a lifting (hydro) prop so a X-437 would be the same as a 1437 except for the design of the prop.