We are getting ready to buy another extender instrument, but we have had bad experiences with the two types we have, the Johnson and the Ludlium extender. We need something rugged,(sand, snow, wind, rain, up and down ladders) and its only use would be to survey under the lifted lid on a cask so it really doesn't need to extend, it just has to have its probe 8' from the readout and read between 100 mR and 1000 R. Any suggestions or comments would be really appreciated.