The following information accompanied stocks from Todd Laverty, UC Berkeley (3/00).
P{w+mW.hs=sevEP-GAL4.B}7 is a homozygous viable and fertile insertion on the second chromosome. The construction and transformation are described in FBrf0125052. This reference also notes that the transposon was constructed in pP{W8}, hence the w+mW.hs marker.