The Universal Iris Slot Holder has been carefully tooled and engineered to fit into many of the new generation of ellipsoidal fixtures including the ETC S4, Altman Shakespeare, Strand SL, and Selecon Pacific Cool Light. An Iris Slot Holder allows a glass pattern to be placed in the Iris Slot of a fixture in the front of the gate, necessary for some thicker glass gobos. In addition the Universal Iris Slot Holder is double sided allowing you to use two gobos, glass and/or steel, in the iris slot at the same time. Use only for 86 mm standard B size gobos.