Made of acrylic, this aquarium probe holder is a secure and reliable placement and holes up to three probes to test different aquarium parameters. The powerful magnets last longer than suction cup probe holders. The Magnetic Probe Holder is ideal for use with pH or temperature probes that may electronically monitor aquarium parameters on a continuous basis. The heavy acrylic construction outlasts suction cup style probe holders without losing its grip. The 3” x 2-3/4” x 1-1/4” high and ½” diameter openings feature adjustable screws to accommodate a variety of items in addition to a probe. The Magnetic Probe Holder can be used to keep airline tubing in place and for use in your sump to securely position outlet tubing of dosing system or use as a magnetic holding rack for your coral frags.