This is the first ocean deployment of two new, high-precision instruments designed to monitor the earth's signals from the seafloor. This housing contains the tiltmeter and nano bottom pressure recorder and the associated electronics and cabling used for power and communications. The instruments were deployed on the seafloor by a remotely operated vehicle as part of the MARS seafloor observatory testbed, located at a depth of 3000 feet in Monterey Bay, and connected to the coast of California 32 miles away by power and communication cables. Tiltmeters detect movements in the seafloor caused by volcanic activity associated with magmatic intrusions and eruptions of submarine volcanoes. The new high-precision tiltmeter inside this housing can detect a tilt or rise equivalent to the height of a penny over a distance of 5 miles. Nano bottom pressure recorders monitor oceanographic and earthquake-generated signals so precisely they can detect a change in sea level as small as the thickness of a piece of paper. The new nano recorders can distinguish between oceanographic signals and seismic signals from earthquakes, potentially improving tsunami forecasts. In this first test deployment in the ocean, they have already detected the ground motion from several large earthquakes, as far from the MARS site as Chile and the Mariana Trench. In the future, the instruments will be part of a global network of cabled seafloor observatories. Because of their precision, these two new instruments are already detecting signals which could never be measured before, revealing new oceanographic, biological, and seismic secrets of our Earth.