These were developed to allow a continuous line of Test Tubes and to keep the Tubes evenly spaced and to prevent the tubes rolling in the outworlds.
They come in twin sets and are designed for 20mm test tubes but can be used on smaller tubes but the spacing of the tubes will be further apart.
These come in sets of 2 and are in three quantity holders:
1 test tube unit
2 test tube unit
3 test tube unit
They can also be sat next to each other to make larger test tube set ups.
FREE postage when combined with a product that has postage included on it.