Modified shape[]
The modified shape has a narrow string gap but not as narrow as a classic shape and is also more rounded. It has become the most popular 2A yo-yo shape and is quite narrow, sometimes narrower than classic. Modified yo-yos are usually good loopers but can also do simple string tricks. Modified shape is also sometimes referred to as Flywheel shape.
Butterfly shape[]
The butterfly shape is excellent for string tricks due to a very wide gap but usually loops very poorly. Butterfly shaped yo-yos are favoured in 1A, 3A, 4A (OS) and 5A (FH). They can have either a rounded or 'v-shaped' profile (see pics) and which one to use tends to be a matter of the yo-yoer's preference. Yo-yos intended for OS play are very wide (see pic above) and v-shaped to make the initial throw and catch easier. H-shape is very significant because it has more rim weight than other shapes.