I have a sterling silver harley davidson ring. Inside it has 925 300 harley symbol and a sun symbol. What does the 300 and sun symbols mean?

I figured out the 10k is for 10 karats, but what is the rest? I know nothing about this piece since it was a gift from my son, who recently died. I don't know where he got it, whether its an antique, or bought new. Can anyone help me, please?

My ring has 5 numbers then 18 ci plat written in it what does this mean ?

I have an 18 karat gold ring (750 stamp) it has 5 small diamonds also and I want to know if the other markings - 1003-6 are reference to their value?

I have an old ring. It says 14ktp, and in cursive capital letters R.M.B inside. Could the R.M.B mark be the maker or hallmark? If so what company? Who made it? The ring belonged to my grandmother and her initials were not rmb. I'm 40 so the ring has to be over 50 yrs oldmaybe even 60. Could...