A temperature therapy pack for providing hot and cold temperature therapy to a body part, and which displays color to indicate different therapy pack temperatures, comprising: a visually transparent temperature therapy pack enclosure, and a reversible thermochromic, thermal exchange material enclosed in said visually transparent temperature therapy pack enclosure, said reversible thermochromic, thermal exchange material being so compositionally and chemically configured that it is capable of being alternately heated and cooled to provide heat or cold therapy, said temperature therapy pack being so configured that, when it is heated or cooled, said reversible thermochromic, thermal exchange material retains heat or cold, respectively, so that said temperature therapy pack can be applied to a body part of a user to provide hot or cold temperature therapy, said therapy pack characterized in that: said reversible thermochromic, thermal exchange material comprises first and second thermochromic agents and a hydrogel formed into a plurality of structurally durable beads, wherein said first and second thermochromic agents are thermochromic pigments in the form of a powder with a particle size in the range of 5-20 micrometers, wherein said first thermochromic agent is configured to display a first color above or below a first threshold temperature and decolour below or above the first threshold temperature, respectively, wherein said second thermochromic agent is configured to display a second color above or below a second threshold temperature and decolour below or above the second threshold temperature, respectively, the second threshold temperature being greater than the first threshold temperature; said therapy pack being further characterized in that said reversible thermochromic, thermal exchange material is so compositionally, chemically configured such as to: display a first color within a temperature range T1 between the first threshold temperature and the second threshold temperature; display a second color within a temperature range T2, which is above said second temperature threshold; and display a third color within a temperature range T3, which is below said first temperature threshold. said reversible thermochromic, thermal exchange material comprises first and second thermochromic agents and a hydrogel formed into a plurality of structurally durable beads, wherein said first and second thermochromic agents are thermochromic pigments in the form of a powder with a particle size in the range of 5-20 micrometers, wherein said first thermochromic agent is configured to display a first color above or below a first threshold temperature and decolour below or above the first threshold temperature, respectively, wherein said second thermochromic agent is configured to display a second color above or below a second threshold temperature and decolour below or above the second threshold temperature, respectively, the second threshold temperature being greater than the first threshold temperature; said therapy pack being further characterized in that said reversible thermochromic, thermal exchange material is so compositionally, chemically configured such as to: display a first color within a temperature range T1 between the first threshold temperature and the second threshold temperature; display a second color within a temperature range T2, which is above said second temperature threshold; and display a third color within a temperature range T3, which is below said first temperature threshold. display a first color within a temperature range T1 between the first threshold temperature and the second threshold temperature; display a second color within a temperature range T2, which is above said second temperature threshold; and display a third color within a temperature range T3, which is below said first temperature threshold.