used by two CBS-affiliated stations (now KSOL and KLLC) in San Francisco. KCBS-FM still kept the oldies format, but shifted its focus mainly to the 1960s decade of oldies with a lesser selection of 1950s oldies, and more early-1970s rock oldies to better compete with KRTH. Arrow 93.1 KCBS-FM struggled with low ratings, while KRTH continued to hold the majority share of the oldies market. On September 10, 1993, at 3 p.m., KCBS-FM flipped to a mixed classic rock and classic hits format, and branded itself as "Arrow 93FM, All Rock and Roll Oldies". The moniker "Arrow" stood for "All Rock and Roll Oldies". The new format focused on the late 1960s and the entire 1970s decade with an emphasis on only classic rock oldies, not including adult contemporary hits, Motown, bubblegum, disco or doo-wop. The Arbitron ratings for KCBS-FM went from 18th to 3rd place by the end of 1993, making the new format an immediate success. The station kept the KCBS-FM call letters, but would only quickly identify its call sign once at the top of the hour per FCC station identification requirements. The format would later evolve towards classic rock of the late 1960s, 1970s, and early 1980s, and re-branded itself as "Arrow 93FM, All Rock & Roll Classics" in 1996. Jack-FM In 2005, Infinity Broadcasting (as CBS Radio was known at the time) won the licensing rights to brand its adult hits music formatted radio stations as "Jack FM". This led to yet another format change for KCBS-FM. On March 17, 2005 (St. Patrick's Day), after an all-day stunt with music from U2 (as that band is from Ireland), the classic rock format was dropped, as "93.1 Jack FM" debuted in Los Angeles, airing an adult hits format that started in Canada and was getting picked up in numerous U.S. markets. The Jack format was a break from the heavily niched formats that had developed beginning in the 1970s. Jack was also unusual in that it employed no DJs, and had a much larger playlist than the typical classic hits or classic rock radio station. The Los Angeles incarnation of Jack includes more modern rock titles than most Jack outlets, reflecting the local influence of KROQ-FM during its alternative heyday. Initially, KCBS-FM played a blend of pop and rock hits from the late 1960s to late 1980s, with a sprinkling of newer, sometimes almost current, tunes.