Hubbell Marine's new 30A/125V Twist-Lock Circuit Tester takes the guesswork out of shore power when coming in to port.  This new handy device plugs in to any 30A/125V locking receptacle. The LED display immediately identifies if the connections are properly made or if there is an issue to address. The compact yellow tester comes with a quick-guide card and a clip to attach it to a tool belt. The circuit tester is $89 from Hubbell Electric Marine Products.