These are nice little heatsinks that measure 43mm x 40mm x 37mm and weigh 80g. They are ideal for cooling power LEDs up to a 3 watts or more.
They are designed originally as a universal Southbridge heatsink, but are perfect for LED cooling where you need a lot of cooling in a compact space.
Made of copper anodised aluminium. Comes complete with some mounting hardware, though that may not be of use for LED work.