From Dave Stafford;
Arm-Safe is an external port mounted on the side of the aircraft, or any convenient location and simply requires a Dean’s shorting plug to arm your aircraft. According to the vendor “when the ArmSafe System is correctly installed and correctly used it can help improve the safety and convenience of electric RC models. The system provides the user with more control of WHEN they energize and WHEN they de-energize their models”. Click this link for more details.
Here’s an example of an Arm-Safe installation on one of Dave’s planes;
I discovered a nice benefit to using all-aluminum spinners, such as Tru-Turn, and the larger adjustable aluminum motor mounts rather than the small X-mounts usually supplied with the motor. They serve as very effective heat sinks for your motor!