Clearblue is # 1 OB-GYN Recommended Brand*nTypically identifies 4 or more fertile days to get pregnant** - at least 2 more days than any other ovulation testnClearblue Advanced Digital Ovulation Test is the only ovulation test to accurately track 2 key fertility hormonesnThe Clearblue Digital Ovulation Test is easy to read - unique digital u0026#39;smiley faceu0026#39; resultsnThe Clearblue Advanced Digital Ovulation Test is the only one that typically identifies your 4 best days to get pregnant naturally-2 more days than any other test [1]. It identifies your 2 Peak Fertility Days by accurately tracking 2 key fertility hormones, luteinizing hormone (LH) and estrogen, plus your 2 typically High Fertility Days before that. So you have more opportunities to get pregnant naturally [2].