This item contains four test tubes with lips connected by sprues.
The lipped tubes fit into a 1/4 inch diameter hole and are designed as bud vase insert tubes. Essentially they are intended to improve the appearance of the hole edges (if you do woodwork like I do) or to add a nice contrasting color ring around the hole. The plastics may not be waterproof so I would stick to using fake or dried flowers in your vase.
The tubes are connected by sprues to reduce cost. They can be cut with strong scissors or wire cutters and any remaining stubs can easily removed by light sanding or filing.