Contains a single FRT site, the lncRNA:roX1 locus (including the chromatin entry site) and a loxP site. Generated by P1cre-mediated excision of the loxP-flanked sequence from any of PBac{(roX1).w+mC.(1.688-3F)}, PBac{(roX1).w+mC.(1.688-3C)} or PBac{(roX1).w+mC.(1.688-1A)}.