Amphenol Sine Systems Rectangular Connectors - Accessories AT06-4S-CAP is a protective cap designed to fit the AT Series of rectangular connectors. This cap is made of a durable plastic material and is designed to protect the connector from dust, dirt, and other contaminants. It features a 4-position design and is easy to install and remove. The cap is also resistant to UV rays, chemicals, and extreme temperatures. It is an ideal solution for protecting your AT Series connectors in harsh environments.