Lowrance X25 sonar / fish finder cone angles

[jurgenscraft]

I recently acquired this old, in excellent condition sonar unit,I was also able to down load a handbook off the web .I would like to know which transducer I have fitted to the unit what is the cone angle of the particular transducer I cant seem to find a part number on the transducer, is there any way of finding out if the unit is a 8 or 20 degree transducer, from what I understand the fresh water unit should be 20 degrees and the salt water unit should be 8 degrees . I swould the standard unit to be the 20 degree unit.