Ameda Egnell and Avent now make pumps that can be easily operated with one hand. The design of these pumps allows the mother to pump while nursing . Another type is the battery operated pump. They are small and can be used with one hand. Most do not have automatic rhythmic suction.
Milk flows directly into a standard bottle.
The biggest complaint about these is the short life span of the batteries. And the suction gets less as the battery gets weaker. However, some of the battery operated pumps can be converted to electricity with the use of an adapter. These are only recommended for short term, occasional use. If you have a preemie who must remain in the hospital a long time or if you plan to pump at work, you will need a more substantial pump.