Many thanks for the six test balls that I received about a month ago. I've tried both the red number & black number balls & found the red a slightly harder ball which goes further off the club face but still has good feel around the green. I've now played five rounds with the same red numbered ball with consistent scores below my handicap. Having only played one round with the black numbered ball I found this a softer ball with better feel around the green. I would personally use the red in the winter & the black in the summer.