allowing {HEAD ~ the second reagent} to be absorbed through the top layer of the pad to activate {TAIL ~ the first reagent} by flowing through the rupturable seal after breaking to form an activated chemical test pad in the sealed package 
allowing { HEAD ~ the second reagent } to be absorbed through the top layer of the pad to activate { TAIL ~ the first reagent } by flowing through the rupturable seal after breaking to form an activated chemical test pad in the sealed package
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL 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