Alternative to Sodium Acetate Trihydrate

[Ralph01]

Hi, I am final year student looking to implement a heating device similar to a hand warmer to one of my projects. The problem is that I need it to heat to a temperature over 55C, ideally it would generate a heat over 75C. Is there a similar process that incorporates a clicker and can be reused?

many thanks in advance

[Borek]

I think sodium thiosulfate was used for the same purposes, but I am not sure about energetic efficiency.