This adapter is designed to hold the following:
50 mL Conical Tube

These adapters will hold 7 tubes. In other words, each adapter has 7 slots.
Your purchase includes four (4) adapters.
This means you will be able to spin a total of 28 tubes with this purchase.

This Adapter Works with the Following

4 x 750 mL Round Buckets

4 x 750 mL Buckets