One-piece softball bats use the same material throughout the entire design. The advantage of the one-piece design is that you get a stronger, stiffer bat that is generally favored by power hitters looking for as little flex as possible. In two-piece softball bats you'll find that the handle is a separate piece from the barrel and that the two are bonded together. The advantage to a two-piece bat is that it's design allows the barrel to flex at the point of contact creating a trampoline effect off the barrel. Two-piece bats generally have less vibration in the handle due to the separation of the handle and barrel.Alloy vs. Composite vs. Hybrid
Alloy bats are generally constructed with a one-piece design out of aluminum or aluminum that is mixed with other metals to make a stronger product. The advantage to this strength is that it allows alloy bats to have thinner, more responsive barrel walls. Composite bats, on the other hand, are made out of a mixture of carbon fiber, graphite, fiberglass, and sometimes Kevlar. Many baseball leagues are beginning to ban composite-barreled bats because, as they are used, the carbon fiber weave begins to become more responsive and much "hotter" than the current standards allow. These new rules have not affected softball but it's always a good idea to check your league rules before buying a composite-barreled bat. Hybrid bats feature a two-piece design in which an alloy barrel is bonded to a composite handle. This makes the handle lighter and allows the alloy barrel to be made longer than on a traditional alloy bat.Single-Wall vs. Double (Multi) Wall
Many slow pitch bats are now made with two or more barrel walls. Multi-wall bats are generally thought to have more trampoline effect due to the fact that there are more layers to provide the spring action. Multi-wall bats also tend to be more durable, as the barrels are usually thicker and sturdier. So why swing a single-wall bat? Many leagues mandate that players are only allowed to use bats with a single wall. If you are in one of these leagues, don't worry, there are plenty of great single-wall bats out there that have as much, or sometimes even more, pop than multi-wall bats. Just type "single wall" into the search box and hit enter. Then click on the "Slow Pitch Bats" filter on the left-hand side to find a great selection of single-wall slow pitch bats.Balanced vs. Endload vs. Maxload
A balanced bat is one that has an evenly distributed weight from knob to endcap and are the most common type of bat. Balanced bats are preferred by players who consider themselves contact hitters and players looking to control the bat and placement of the ball better. Endloaded bats usually have an extra half ounce or so of concentrated weight at the end of the bat near the endcap. This gives the hitter extra momentum when swinging through the ball. This type of bat is usually preferred by power hitters that like to swing for the fences. A maxloaded bat is very similar to an endloaded one, except that there is more weight at the end. This type of bat should only be used by stronger players that have no problems controlling their swing.ASA, USSSA, and Other Associations
ASA is usually considered to be the most highly regulated association in softball as they generally have the strictest guidelines for bats. The major difference between bats made for ASA play and all other associations is performance. For instance, ASA approved bats must adhere to the 98 mph batted-ball speed standard, while bats approved for USSSA and other associations are allowed to have a much hotter 100+ mph batted ball speed and a bat performance factor (BPF) of 1.20 or sometimes more. You can find a full rundown of rules and regulations here.Wood
Wood bats are most commonly made from either Ash, Maple, Bamboo, or Composite Wood. Maple is stronger than Ash, while Bamboo serves as the strongest and tends to last a little longer than most wood bats. Ash is bit softer which allows it to flex during the swing and produce a great whip through the hitting zone to give players better bat control. Maple is harder and denser than ash. Many power hitters like maple because the hardness and stiffness allows them to exert as much force as possible onto the ball. Composite Wood bats are a mixture of wood and composite materials. They are very durable and high performing but may not be legal in some leagues.