The apparatus comprises {HEAD ~ an elongate base} having {TAIL ~ means} on one end for mounting the base on a laboratory ring stand and means on the other end of the base for allowing a technician to hold the microcentrifuge tube in one hand and to open and close the cap without requiring a second hand 
The apparatus comprises { HEAD ~ an elongate base } having { TAIL ~ means } on one end for mounting the base on a laboratory ring stand and means on the other end of the base for allowing a technician to hold the microcentrifuge tube in one hand and to open and close the cap without requiring a second hand
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH