octura prop ID

[boogeyman]

need some help w figuring out octura props
i undersand that the last 2 numbers are the diameter but the letter and the first number i still dont get
for example whats diffrent between a x642 and a m642 ?

[andym]

The x and M series are the same prop minus the tongue. For our FE application little or no tongue is better due to the high rpm.For this reason I detoungue all X series.This along with other mods to unload our props and achieve max rpm is the way to go.
Some reading for you
http://www.funrcboats.com/prop_chart1.htm

http://rcprops.com/

http://rcboat.com/prop.htm

Just a few of the sites but you will get the idea