Shelf-lievel selling! I have no idea what that means, unless it's the idea that radio ads have the same impact as seeing an item at eye level. I don't know what else it could mean.

Wikipedia:

WSAI radio was established by the United States Playing Card Company in 1923, and originally transmitted broadcasts from their facilities on Beech Street in Norwood, Ohio. [4]

In 1928, the station was sold to Crosley Broadcasting Corporation, because WSAI's then transmitter site in Mason, Ohio was seen as an ideal site for WLW's new 50,000 transmitter (and later 500,000 watts in the mid '30s). WLW kept WSAI as a locally-oriented sister station, while WLW — with programs from NBC Radio and the Mutual Broadcasting System — aimed for the whole region.

By the time of this ad - 1949 - it had gone over to a music format. It was Cincinnati's most influential Top 40 AM statoium in the 60s and 70s, he said, finding a way to paraphrase some more Wikipedpia.