This propeller is marked 16 x 15.

The first number 16, is the Diameter in inches and the second number 15, is the Pitch of the propeller in inches.

Sometimes it may be necessary to contact a Dealer for the propeller size quoting a part number.

"48 19638 A40" Is the manufacturer's part number and the "11P" is the propeller pitch in inches.

Above is a 9 3/4" * 17" R (Right Hand)

Above is a 10" * 13" They can be very hard to read.

But most are pretty easy to identify.

A rough guide to propeller diameters are as follow-

9.9 - 15HP 9 - 10"

25 -30HP 10" - 10 3/8"

40 -70HP 10 3/8" - 12 1/4"

70 -140HP 13 1/4" - 14"

V6 -Stern Drive 14 1/4" - 15"

Larger Stern-drive 15" -up