The lens sheets in Stagebar 54 fixtures from S/N 4354630001 have magnetic mountings, making lens removal or installation possible without tools (see page 20 of the Stagebar user manual Rev. E). Magnetic mounting lens sheets (PN 41350030) can only be installed in earlier fixtures with screw-mount lens sheets if you also replace the screw-mount lens sheet mounting pillars with magnetic-type pillars (PN 08053859).