Changes

# The P165(P165-A) Embedded Armor Aluminum Alloy Heatsink Radiator is 7mm high (designed with negative tolerance) and is equipped with M2.5*5+5 copper spacers; so the total height is 12mm, which can support most of Raspberry Pi 4 expansion boards(not support PoE expansion board); if you use expansion board with other height, you only need to replace the copper spacers with the right height. (If you need a special height copper spacers, please contact us.)

# The raspberry pi hat positioning hole has internal thread for easy fixing from above or below; Compared to the raspberry pi PCB, the entire heat sink shrinks inward by 0.5 mm.

'''Why design this new P165-B 11mm heatsink?'''