Allegro Industries 8414-11 Phase Change Cooling Inserts - Compatible with Allegro PN 8412 & 8413 Series (4-Pack) | Industrial Cooling Solutions for HVAC & Refrigeration Systems

they work great i bought these to replace the one's in my set that went bad after 2 yrs that were a different brand. they work good in the summer time i live in Tampa Fl. so the heat is extreme down here i freeze them in the freezer then put them in my cooler filled with ice and they stay until i need them and also u can freeze them in ice or really cold water takes about 15 minutes that's the reason i bought these some u can't. I usually get about a good 1 hr to 1 1/2 out of them depending on what i'm doing and how hot it is that day i would definitely recommend these to anyone who works in very hot conditions u still sweat but u dont feel like passing out and u keep your energy longer i bought my vest from another company but there are some vest on amazon that these will fit into just got to look them up when it comes time to replace my vest i'll buy one on here next time or another from the company for $45 dollars texas cool vest. but if i need to replace my other set of packs i'll buy more from here i keep 2 sets so 1 is getting cold in the cooler while i'm wearing the other.