Cell Phone Boosters? What are those?

I never knew there was such a thing as a cell phone booster. I mean I don’t keep up to date with the best in cell tech – what with me owning a pay as you go phone. But I do notice at times - maybe due to this apartment being old how - my signal isn’t the best it could be.

Considering that the house phone = cell phone, this leads to a few dropped or fuzzy calls I’d rather not have. Maybe this item is what I need.