直径 33 mm 的比色槽，用于 ASTM 颜色

In order to hold these tubes upright in the correct position, the operator will also need the tube adaptor part number 132810. This adaptor includes a single 352300 tube. Please note that these tubes are shorter than the 33mm tubes used in the Petroleum Oils Comparator (357630) in order to allow the instrument's lid to be closed.