IMS (Insulated Metal Substrates) are laminates with an aluminum core, mostly used for their high heat dissipation properties. 

IMS PCBs are mainly used for LEDs and Power supply applications.

Safe-PCB offers single and double side IMS.
Two different stacks are configurable in the case of double-sided (see below).

Optionally, it is possible to cover one side of the PCB with an adhesive 3M-9460

Often, the soldermask selected by customers is black (matt or glossy) or white. This choice of color is dictated by the need to reflect or absorb the light generated by the LEDs on the card.

Safe-PCB offers 7 IMS references:

BOYU AL-01-B-10 - 1,0 W/mK
BOYU AL-01-B-15 - 1,5 W/mK
BOYU AL-01-B-20 - 2,0 W/mK
BOYU AL-01-B-30 - 3 W/mK
BOYU AL-01-B-50 - 5,0 W/mK
BOYU AL-01-B-80 - 8,0 W/mK

There are different thicknesses of insulation between the copper and the aluminum base of SMI substrates. Safe PCB offers the thickness 120 µm by default