These are 3D printed EGR Block off plates for the 1st gen 1UZ intake (non-vvti). Printed with carbon fiber reinforced plastic that is chemically resistant to fuels, oils, and other liquids that might find their way into the engine bay or your engine. Temperature resistant up to 140C (284F) for prolonged periods of time and up to 200C (392F) for short term exposure. 
 
Included in the listing are 2 pieces, one for the large side port, and one for the rear port. Here's the listing for the same part with a barb fitting added for the PCV vacuum hose. 
 
Paint does not stick well to this material and the finish of the print may vary from the pictures. For installation RTV is recommended to properly seal to the intake and original hardware can be reused.