Durable Proximity Shields from Supra contain the signal from keyless-entry devices. The shield enables you to store the keys safely within your Indigo Key Box without releasing an “open” signal to unlock the car. The Proximity Shield fits easily inside the Indigo Key Box, holding a variety of key shapes and sizes. Constructed of lightweight aluminum, the shield encases the keyless-entry key so that “open” signals cannot be transmitted to the vehicle.