Gelex secondary standards kit for 2100P and 2100Q series portable turbidimeters (includes 1 sealed vial each for 0 to 10 NTU, 10 to 100 NTU, 100 to 1000 NTU).

Gelex secondary standards kit for 2100N and 2100N IS series laboratory turbidimeters (includes 1 sealed vial each, Stray Light Standard, 0 to 2 NTU, 0 to 20 NTU, 0 to 200 NTU, 200 to 4000 NTU).

Gelex secondary standards kit for for 2100AN and 2100AN IS laboratory turbidimeter (includes 1 sealed vial each, Stray Light Standard, 0 to 2 NTU, 0 to 20 NTU, 0 to 200 NTU, 200 to 4000 NTU, 4000 to 10000 NTU).