Hi mama! Honestly, I'd be careful with secondhand fetal dopplers kasi mahirap malaman kung reliable pa talaga ang reading, at ang peace of mind mo baka maging worry pa lang if something's off or unclear, a few of us tried it and nag-stress pa kami instead of relaxing, hehe. Better to use the one sa clinic during your regular checkups, or kung kailangan mo talaga ng home monitoring, maybe better to get a new one from a trusted medical supply store so you know it's accurate and safe for baby.