The D3 is designed to perform reliably and consistently under the most demanding conditions. The exterior of the D3 is crafted of magnesium alloy, and numerous seals are used throughout the body to protect the camera against dust and moisture. The camera’s shutter employs blades made of a hybrid of carbon fiber and Kevlar and is tested to 300,000 cycles. The camera also features a Self Diagnostic Shutter Monitor that ensures the accuracy and precision of the shutter at all times.