What types of Youth baseball bats are there?

One-Piece vs. Two-Piece

One-piece baseball 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 baseball 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 its 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 barre

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 can 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 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. 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.

Wood

Wood bats are most commonly made from Ash, Maple, Bamboo, or Composite Wood. Maple is stronger than Ash, while Bamboo serves as the strongest and tends to last a little longer. Ash is bit softer which allows it to flex during the swing and produce a great whip through the hitting zone leading to better bat control. Maple is harder and denser than ash. Many power hitters like maple because of the hardness and stiffness so that they can exert as much force as possible onto the ball. Composite Wood bats are a mixture of wood and composite materials. They are very durable but are not legal in many leagues. Youth wood baseball bats generally have an approximate length to weight ratio between -4 and -8.