Yamaha prop question

I dinged my factory standard aluminum prop on my 40hp 2stroke Yamaha(1999). I was thinking about getting a SS prop and having this one repaired for a spare. Friend of mine loaned me a few with different pitch and diameter to see which one works best. All but one have the letter (G) following the diameter and pitch info. Can someone tell me what the G denotes?
Thanks.y

The letter denotes the HP range of motors the prop fits : Propellers | Yamaha Outboards

Thanks. Could not find that in my digging around the internet.