The WarmMark^® Duo Time-Temperature Indicator is a single use label typically applied to vaccines, pharmaceuticals, and blood products for monitoring conditions during storage, shipping and distribution. It has two response temperatures indicating accumulated time above 50°F/10°C, and brief temperature excursions above 93°F/34°C.

WarmMark^® Duo Time-Temperature Indicator, Model 51036, is a single-use thermal label designed to monitor temperature of blood and blood products, vaccines, and other pharmaceuticals during storage, shipping and distribution. It responds at two temperature thresholds, and is used for products with a known stability curve and with identified expiration characteristics for a specific time/temperature combination.

This cost-effective, self-adhesive label can be applied directly to a product and easily fits inside temperature-controlled packaging. When activated, the indicator windows remains white unless the label is exposed to temperatures above 50°F/10°C, then an irreversible red color migrates progressively towards the three windows. If the temperature goes below threshold, the color stops advancing. The first three windows indicate accumulated time above threshold, when colored red they denote exposure up to 3 days, 8 days, and 14 days. The fourth window indicates brief high temperature excursions, and turns red if the temperature goes above 93°F/34°C for at least 30 minutes.

WarmMark^® Duo shows at a glance if temperature abuse has occurred and for how long, thus providing visual evidence for making immediate decisions on whether product safety, efficacy and quality have been jeopardized.