The fetoscope is the modern combination of both the stethoscope and the Pinnard Horn. It uses the practitioner's forehead to conduct sound and has a more modern look to he whole device, being made from metal and plastic compared to the wooden Pinnard Horn. It does not use ultrasound.
Some practitioner's like to use this at every visit from about week 12, though many won't hear the heart beat that early. This device takes a skill at listening, but when practiced properly a doctor or midwife can tell the baby from a placenta with this device. The sound of the baby's heart beat sounds like a watch under a pillow.
Some models also attach the listening device over the head of the wearer. This allows one to be more hands free, particularly during a birth.