A small submachine gun with underbarrel railgun and cloaking device.
Protector (1973). Cover illustration by Dean Ellis. The back cover shows the rest of the ring world, which actually is quite a magnificent sight. The ring concept—or “Dyson sphere”—is a popular one of course, appearing in various sci-fi and fantasy stories; I’ve posted illustrations depicting this same structure before. I googled “ring world”, and Google suggested “Molly Ringwald”.