• Sealer bar width.The sealer bar is the part of the sealer that melts the two sides of a vacuum storage bag together to create an airtight seal. It also determines the widest bag the sealer can use. For example, if a sealer has a 12" sealer bar, you will not be able to use bags wider than 12" at most. For best results, you will want to use bags narrower than the sealer bar to ensure a tight seal all the way across the bag.

• Automatic and Manual Models.Most vacuum sealers come with an automatic mode. This mode does most of the work for you by testing the air pressure in order to shut off when a certain pressure is attained, then automatically starting the sealing (and sometimes bag cutting) process. For most casual users, this is ideal and takes much of the guess-work out of vacuum sealing foods.

• Variable Pressure. While most models deliver a single vacuum pressure, some units allow the user to set the amount of pressure for greater control. Again, this is more or less important depending on how you plan to use your vacuum sealer. More delicate items may require more gentle pressure to avoid damage (some models boast the ability to crush aluminum cans, after all). If the condition of the item being sealed is important, finding a unit with variable pressure may be important to you.

• Multiple Sealing Wires. Most models seal the bags by using heated wires to melt the bag sides together. Having more than one sealing wire provides a much lower chance of tiny gaps in the seal, which let air back into the bag. Most models will have two wires or a much wider heating bar to ensure a tighter seal. These models are typically used as commercial vacuum sealer. For the most part, how well a bag is sealed has as much to do with the operator as the unit, so this may or may not be as critical a feature.

• Continuous Seals. Some models support the ability to produce multiple sealed pouches in a continuous row. For example, a user could seal pasta, meatballs, and sauce in three separate pouches, but leave all three still linked together as a single package. Most models only allow for one seal per pouch, but some make it possible to seal one pouch after another without cutting between each pouch. This can be a handy feature but may be less important to some users.

• Automatic Bag Cutter. If cutting bags yourself is a hassle, then you may want to consider a unit that cuts the bag automatically. This is more important when using rolls of sealing plastic instead of individual pouches. A bag cutter can be quite convenient, especially when sealing multiple bags in a single session. On the other hand, it is one more moving part that could break and will likely need maintenance or replacing after the cutter becomes dull.

Take a little time to consider what you might use your machine to do. If your goal is more efficient storage and packaging of leftovers, you may consider a unit that can package separate ingredients in a single, continuous string of pouches in order to keep the entire dish or meal conveniently grouped together.