Get accurate spin RPM and axis for a fraction of the cost of the Rapsodo RPT balls.
Use your favourite golf ball instead of a Callaway.
Best used with Sharpie ultrafine pens (Walmart and other places sell them). Even my 3 year old granddaughter marked a ball! It takes less than two minutes to mark a ball.
I pick so many abandoned balls up at my local course that I have free RPT balls for life.