type of tub for snake rack

What type of tub I need for a rack n holds heat without melting?

All plastic tubs are fine to use in a rack. They won't melt as long as you have regulated heat. (heat tape or heat mat connected to a thermostat)

And plastic tubs do not really hold heat well, so make sure your ambient temps are good or your rack is insulated.

I suggest looking at IRIS tubs. They are more expensive than other tubs, but their tubs never change styles so its easy to find replacements. Sterilite or Rubbermaid are popular, but they change tub designs often, so finding replacements in the future will be difficult unless you stock up on a bunch.

I like the Vision tubs...even my non-vision racks have vision tubs.