TL Reefs Magnetic Probe Holder Color:Black • 5) Keep significant aeration

•       5) Keep significant aeration in aquarium system

This holder will keep all your probes secured and out of the way

or stop and restart the pump

This set includes two switches

for easy identification

TL Reefs Magnetic Probe Holder Color:Black • 5) Keep significant aerationThis holder will keep all your probes secured and out of the way. 1 hole is 0. 65", for temperature probe. 3 holes are 0. 55" for other standard probes, such as pH, ORP, etc. Strong Neodymium magnets combined with a grippy oring hold the box securely in place on aquarium thicknesses up to 3 4" Magnets are completely encased in cell cast acrylic and will never get water in them. No worries about rusting magnets causing water quality issues. Thumb