Tender For supply of ventilation instrument for mine - whirling type hygrometer , digital lux meter range 0 to 50000 lux , digital anemometer as per detailed description , digital multi gas detector portableand dgms approved with accessories for measuring o2 ch4 co and h2s as per detailed description , noise dosimeter as per description , personal dust sampler with rotometer as per dgms guideline and annexure , velocity pressure meter as per annexure