The LifeDop 150 features a non-display, hand-held Doppler with superior sound quality, extended battery life, enhanced probe sensitivity, interchangeable probes and a one-year full warranty. Probe Choices: All probes are interchangeable. Obstetrical Probes SD2 - 2MHz Probe The 2 MHz obstetrical probe is optimized for deep penetration and third trimester pregnancy. SD3 - 3MHz Probe The 3 MHz obstetrical probe is optimized for early fetal heart detection and designed for use during the entire pregnancy (It is the best general purpose obstetrical probe). SDE - EchoHeart Transvaginal 5MHz Probe The EchoHeart 5 MHz transvaginal obstetrical probe is optimized for earlier fetal heart detection and ideal for retroverted and obese patients. It is used when transvaginal imaging is too costly or inconvenient. SDW - 2MHz Waterproof Probe The 2 MHz Waterproof probe is for obstetrical use in water applications, and in the labor and delivery department where the probe needs to be waterproof. Vascular Probes SD4 - 4MHz Probe The 4 MHz vascular probe is designed to ease location of blood vessels. The broad, wide-angle beam has internally tilted crystals that are optimized for quickly locating vessels. SD5 - 5MHz Probe The 5 MHz vascular probe is designed to ease location of deeper vessels. The medium width beam and pencil-style shape provides optimum sensitivity and ease of use. SD8 - 8MHz Probe The 8 MHz vascular probe is designed to ease location of surface vessels. The narrow beam and pencil-style shape provides optimum sensitivity and ease of use (It is the best general purpose vascular probe). The LifeDop 150 features a non-display, hand-held Doppler with superior sound quality, extended battery life, enhanced probe sensitivity, interchangeable probes and a one-year full warranty. Probe Choices: All probes are interchangeable. Obstetrical Probes SD2 - 2MHz Probe The 2 MHz obstetrical probe is optimized for deep penetration and third trimester pregnancy. SD3 - 3MHz Probe The 3 MHz obstetrical probe is optimized for early fetal heart detection and designed for use during the entire pregnancy (It is the best general purpose obstetrical probe). SDE - EchoHeart Transvaginal 5MHz Probe The EchoHeart 5 MHz transvaginal obstetrical probe is optimized for earlier fetal heart detection and ideal for retroverted and obese patients. It is used when transvaginal imaging is too costly or inconvenient. SDW - 2MHz Waterproof Probe The 2 MHz Waterproof probe is for obstetrical use in water applications, and in the labor and delivery department where the probe needs to be waterproof. Vascular Probes SD4 - 4MHz Probe The 4 MHz vascular probe is designed to ease location of blood vessels. The broad, wide-angle beam has internally tilted crystals that are optimized for quickly locating vessels. SD5 - 5MHz Probe The 5 MHz vascular probe is designed to ease location of deeper vessels. The medium width beam and pencil-style shape provides optimum sensitivity and ease of use. SD8 - 8MHz Probe The 8 MHz vascular probe is designed to ease location of surface vessels. The narrow beam and pencil-style shape provides optimum sensitivity and ease of use (It is the best general purpose vascular probe).