Liquid Nitrogen or Dry ice and alcohol

X2 about the frost. You can get a styrophoam cooler to put nitro in temporarily while branding. The length of time varies for type of brand..brass..steel..and also thickness of skin for each dog. On average I use brass 2in with nitro leave brand in nitro until it quits boilng and gets a good frost halfway up handle. I burn em round 8sec for dark dogs and 13 to 18 sec for light dogs. As soon as you let off the burn the indention of brand will raise on skin and then disappear. Make sure you get all the hair shaved in spot and keep it good and moist with non isopropal alcohol. Tip for first timers...get some buddies to help hold dog down and duct tape feet and mouth. Have buddies lay across dog while doing burn NO MOVEMENT. Rock brand in 360 circle. If I can help anybody further just pm me. Its a great tool coupled with tags and tattoos. Good Luck.