Comparison : Item # QSI-66-1, QSI-66 Stirrer and Stir-Tester, Glas-Col, G.K.H., Model HST10
Item # QSI-66-2, QSI-66 Stirrer and Stir-Tester, Glas-Col, G.K.H., Model HST10
Item # QSI-66-3, QSI-66 Stirrer and Stir-Tester, Glas-Col, G.K.H., Model HST10