What does medium height mean to you? Where in general are you located?

What do you consider to be "medium height"?

A number of arborvitae cultivars, Thuja occidentalis, will stay very close to that width if not within it.

Other possibilities might include Ilex crenata 'Sky Pencil', Euonymus japonicus 'Green Spire', Cupressus sempervirens 'Tiny Towers' or 'Stricta'.

Also Juniperus 'Taylor'--very, very narrow.

i'd like a height of no more then 15 to 20 feet.

I’ll second Juniperus ’Taylor’. Tight and narrow. It would really help to know your location, but if east of the Mississippi River, this would be a better choice than J. scopulorum.

A general location -- city, state, climate zone -- would be most helpful.

i went with Blue Arrow Junipers. BTW I an on Long Island, NY.