Rv Led Black Double Tank Water Level Indicator Tame Your Tanks With A Customisable Kit! Choose Between 2.5M, 5M And 7.5M Sender Probes And Keep An Eye On Your Dual Volumes With One Press Of The Test Button. No Need For A 12V Supply The Top Gauge Is Battery Powered And Simple To.Measuring Just H65Mm X W65Mm X D16Mm, This Water Gauge Fits Anywhere. Get Ready To Take Charge Of Your Tanks! Suitable For Plastic And Metal Tanks. Easy Installation. Fits Existing Water Tanks Battery Included Suitable For Caravans, Boats And Camper Trailers. 2 X Rv Tank Sender Probes Required. H65Mm X W65Mm X D16Mm. This Easy To Fit Tank Sender Probe Only Requires One 22Mm (7 8 ) Hole In The Side Of The Tank And Suits Tanks From 100Mm To 280Mm (4 To 10 ) Deep. The Sender Probe Is Sealed By A Special Grommet Which Is Compressed In The Hole When The Nut Is Tightened And Measures The Water Level By Contact With The 5 Sensors Along The Arm. It Has No Moving Parts.