He developed Supp-Hose uplifting hosiery. His paternal cousin was Felix Zandman who founded Vishay Intertechnology Company with capital from Slaner.
Slaner graduated from the University of Oklahoma, and then went to work for his uncle, at the Chester H. Roth Hosiery Company eventually becoming president and negotiating its 1958 merger with Julius Kayser & Co to become Kayser-Roth. He remained as president until Kayser-Roth was sold to Gulf and Western in 1975.