The apparatus, which may have {HEAD ~ a configuration} similar to that of a felt tip marking pen, allows {TAIL ~ convenient use} of low volatility solvents in the catalyst solution 
The apparatus , which may have { HEAD ~ a configuration } similar to that of a felt tip marking pen , allows { TAIL ~ convenient use } of low volatility solvents in the catalyst solution
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH