The ILA-TIM-SQUARE series, from Intelligent LED Solutions, are a family of thermal heat pads designed specifically for LED squares (58x58mm). They are available in non-adhesive or single/double sided adhesive options.
"Features of the ILA-TIM-SQUARE single-sided and non-adhesive:
Colour: pewter
0.13mm thick
Temperature range: -240°C to +300°C
Features of the ILA-TIM-SQUARE double-sided:
Colour: cream
0.16mm thick
Temperature range: -240°C to +300°C"