In the last 90 days, 1 listings have been listed, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 100% of the available space in the Rockville are subleases, so you might be able to find a shorter term or below market rent. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around sqft. Most buildings in this market are around 3 stories. Most buildings in this area were built in 1963 and are Class C.