Also the height of {HEAD ~ the top wall} above {TAIL ~ the conveyor} is sufficiently small to accommodate only the environmental sensors, the assay cartridges, and a clearance space between the sensors and the cartridges 
above
Also the height of { HEAD ~ the top wall } above { TAIL ~ the conveyor } is sufficiently small to accommodate only the environmental sensors , the assay cartridges , and a clearance space between the sensors and the cartridges
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH