We need 31 cm & 43 cm to test their gauges. Since we want a continuous fuel level sensor can you explain what you have. Please send the technical data sheet to understand how your hydro static sensors work in actual. What is the signal output which we get; is it resistance or voltage & at what input volt range it works ?? Does it sense continuously or fails to read between switch levels & can we get length of 30 cm in your stock to test it in our workshop !! Their gauges should operate on 12 to 24 V both and if we can negotiate a prices for the above given required sizes. If its 18-20 $ landed at India; its workable provided their gauges are made on one standard and do not have different ohmic ranges. Please revert the needed asspects to follow the order of devices followed.