Biodegradable heat packs generate their own heat, reaching and maintaining temperatures between 100° and 158°F. Average temperature is 124°F (51°C). Based on an ancient Chinese formula, packets contain a mix of iron powder, active carbon, water, vermiculite, salt, and Cellulose. Sealed packets are air-activated by opening the outer package. They are lightweight, environmentally safe, practical, and disposable. If not completely used, reseal in an air tight container for later use.

Heat packs are 4 x 5" ( 10 x 13cm) and provide upwards to 24 hours of heat in a Berlese funnel. They have a shelf life of four years prior to opening as long as outer packaging is not compromised.

See 2831, 2832 and 2845 for descriptions of three types of Berlese funnels.