Varieties of propellers

Variety of brands, models and capacities of boat motors requires a tremendous amount of propellers.  They are distinguished by:
-Pitch ( the distance a propeller would move in one revolution if it were moving through a soft solid, like a screw through wood.” For example, a 21-pitch propeller would move forward 21 inches in one revolution.)
-diameter (the circle described by the most remote from the center of the blade points)
-Direction of rotation (RIGHT HAND OR LEFT HAND ROTATION) 
-Disk Area Ratio  (ratio of the total area of the blades to the area of a circle with a diameter equal to the diameter of the propeller)
-Amount of blades ( usually 3, at least 4 or 2)
-Material  (The most popular materials used for making marine propellers is aluminum and stainless steel. Other popular materials used are alloys of nickel, aluminum and bronze which are 10~15 % lighter than other materials and have higher strength.)
                       Aluminum                               Stainless steel 
-Design of hub ( rubber damper, removable sleeve ,removable blades)
-the diameter of the hub
-Amount of hub splines