The mast balls are made of Delrin plastic and are intended to be sacrificial...that is that the ball wears away before wearing the base of the mast. A brass ball would tend to wear away the bottom of the mast which would be extremely expensive to repair compared to an occasional $15 plastic mast ball. You might have to wait a little while for shipping but it shouldn't be THAT expensive to get them shipped to wherever you are.

Another thing to consider is that the base of the mast casting is typically very rough and tends to wear the balls quickly. We use marinetex epoxy to make a small putty disk to put in the mast base, wet it with water, and press a mast ball in place to give it shape. Remove the mast ball before it cures completely. This gives a very smooth perfect fit that will give you years of life on the plastic mast ball.