This is the companion lens to our Eltec Pyroelectric sensor. This can be used if you loose, trash, or otherwise render the original unuseable. This is made by Fresnel Technologies and has a part number of 6800408. It is made of a polypropelyne material and is roughly 1" in diameter with a rough cut square of extended material. This includes the pattern for the cone for the Pyroelectric detector lens orientation on thick card stock.