Leviton says the SmartlockPro Slim Self-Test GFCI is about 25 percent smaller than a typical GFCI receptacle, which should make it easier to fit the wires in the box. The receptacle automatically runs a test every 15 minutes to verify that everything’s working properly; if it trips, it cannot be reset if it was improperly wired. The 15-amp GFCI costs about $40.

Leviton Manufacturing Co., 800/323-8920, leviton.com.