GMDB Measurement grid kit for DBM610 instrument Designed for air velocity measurements on any types of large celling vent or diffuser. The grid is similar to the DBM610 grid. It calculates the average air velocity from 24 points to guarantee a reliable measurement.. The grid is attached to a telescopic (maximum length is 2.05 m) and articulated pole (from 0 to 90°). Struts of 3 different lengths allow a correct positioning of the grid on the celling surface. A bagpack allows easy carriage of the grid and its accessories (telescopic pole, articulation, 2 x 2.5 m of silicone tube, positioning struts and electronic housing).