Attributes . On 40-400, 40-410, 40-500, 40-510, 60-400, 60-410, 60-500, and 60-510 models with 20,000 psi, the accuracy is 1.5% or 1.6%.Ammonia gauges are available in these ranges. To order, add "- AMMONIA" at the end of the part number. . Names