MTC products are constructed from materials that are pervious to weather damage. They are intended to be used in any adverse weather conditions without suffering deterioration or affecting performance. However reasonable care is necessary with any accurate instrument. MTC has selected an array of materials that offer weather resistance while providing accurate and consistent data transmittal. The stainless steel pivot shaft is made from 300 series stainless steel, but most stainless steel bearings are made from 400 series stainless steel. This material contains iron for the purpose of heat treating and is rust-resistant, but not totally rustproof. Maintaining clean and contamination avoidance conditions will ensure long and responsive life. This is not unique to the bearings that MTC uses as all stainless steel ball bearings are heat-treated for hardness against ware and must be kept clean and dry or lightly oiled.