Birth Date Finder Wheel Calculator. Screen-printed in 1 spot colour directly on to the .020 White Vinyl Plastic material. This makes for a top quality, long lasting wheel. Use our standard template or supply your own customized one. Ideal for Fertility Clinics, Reproductive Centers, Obstetricians & Gynecologists. Can also be used for Gestational calculations in the livestock industry. Custom imprint, Pantone colour match & bleed edge all included. Top wheel 3.25" dia. & Bottom wheel - 4.25" dia.