These bottles are very similar in use and appearance. Both are Van Dorn samplers that come in the same sizes and in PVC and transparent acrylic. The only differences are in the end seals and latex closing tubing. These differences are enough, however, to make the Beta™ better suited to sampling trace metals.
The blue polyurethane seal used in Alpha™ bottles may leach some mercury and phosphorous (among other contaminants). However, it is durable and long-lived. The white ASA plastic seal used in Beta™ bottles does not leach mercury. However, it is not as durable.
The black latex tubing on Alpha™ bottles is highly resistant to decay from sunlight and water. However, it may leach a very few heavy metals. The amber latex tubing on Beta™ bottles is less resistant to sun and water but does not leach contaminants.