Patent ID: 8273298

Claim:
A device adapted to be worn on the exterior of hunters' odor absorbing clothing, which comprises: (a) a dry reactive chemical powder having granules which undergo a color change when exposed to gaseous nitrogen-containing compounds such as ammonia and amino acids; (b) a two-sided detector packet, the packet having front and rear sides, the front side defining a view aperture and the rear side defining a through opening; (c) a transparent, nonabsorbent tape with an adhesive backing, the tape, which is stretched across the view aperture, being positioned between the atmosphere and the dry reactive chemical powder, a thin layer of the powder being affixed to a portion of the tape's adhesive backing, said portion generally spanning the view aperture, the thin layer so affixed being visible through the tape and kept out of contact with the atmosphere during use; (d) means, including a nonhydroscopic filter media sheet, for generally blocking migration of granules of the dry reactive chemical powder away from the tape's adhesive backing and towards the through opening, the filter media sheet, in use, being positioned between the powder and the odor absorbing clothing; and (e) wherein said thin layer and any powder held between it and the filter media sheet are sufficiently porous that the gaseous nitrogen-containing compounds, once they have traversed the filter media sheet, diffuse rapidly through the powder until they react with powder granules disposed contiguous with the transparent tape.