8 Similar l y t o the s tability o f the tr ip o d tha t o f the tr ib r ach is a signifcan t f ac t o r in me asur emen t ac cur acy T he t o r sio nal r ig idity the mos t imp o r tan t cr it er io n o f a tr ib r ach is c o ns tan tl y c o n tr olled and t e s t ed dur ing its p r o duc tio n T he main t enanc ef r ee f o o t s cr ews o f the Leica G eosys t ems tr ib r ach p r ovide mov emen t tha t is alwa ys smo o th and f r ee o f pla y e v en a f t er y e ar s o f us e T he p r ecis e alignmen t o f the sup p o r t ar e a t o the bas e pla t e o f the ins tr umen t assur e s ex tr emel y ac cur a t e f o r c ed c en tr ing T he o p tical plumme t is s o r obus t tha t the need f o r adjus tmen t dur ing the en tir e lif e time o f the tr ib r ach is p r ac ticall y unnec e ssar y Its c o ns tr uc tio n p r ede s tine s the tr ib r ach f o r all ap plica tio ns including ex tr eme t emp er a tur e s and hig h dus t and humidity o ri ginal T ribra c hs Ac cur acy thr oug h t o r sio nal r ig idity 8