There are many types of refractor on the market. The one to have is the Astronomical Refractor, but not the Terrestrial type. This is because the latter has a number of additional lenses in the telescope to put the image the right way up. Lenses absorb a small amount of light when light travels through them, so extra lenses would cause the image to dim. The astronomical refractor does not use the extra lenses because we need every scrap of light when looking at night sky objects, such as the planets.
Eyepieces are units that fit into a telescope, and vary in design and focal length.
This focal length determines the magnification. You can normally find the focal length of eyepieces written on the top on the side of the eyepiece. Another factor to consider is Focal Ratio. This is a term used by photographers to show how good lenses are at collecting light. Low ratio telescopes give wide fields and are useful for looking at faint nebulae, and other deep sky objects.