Editing Shot clock (section)

===Models===
Originally, the shot clocks used in the NBA were usually single-sided in a black box. A 1991 rule change required game clocks to be included with shot clocks in the NBA.  Eventually, after the rule change, multiple-sided began to be used, and would be in most of the arenas.  A 2002 NBA rule change allowing instant replay review of last-second shots required four-sided units in NBA venues, along with an accompanying shot clock light to determine if the shot went off in time.  In 2005, the [[FedExForum]] in Memphis opened with a new two-sided transparent shot clock developed by [[Daktronics]] with a smaller secondary version also accompanying the larger one.  By the 2010's, the twin shot clock format, used by Daktronics and Canadian rival OES, became the standard for most venues, especially in NCAA play.  In the [[2014-15 NBA season|2014-15 season]], the NBA signed a deal with Tissot, a Swiss watch company, for specification two-sided transparent shot clock, which was thinner than its predecessors. But in many international leagues and the collegiate level, the older 3-sided and 4-sided shot clocks are still in use, except for Daktronics, OES, and SwissTiming/Tissot venues.