Chip for the Ultimate3/3S QRSS kit, v3.09f. This is the ATmega328 chip.

Note that this is the chip for the Ultimate3/3S Kit, it will work in both the U3 and U3S kits. But it is not for the older retired Ultimate (U1) kit or Ultimate2 (U2) kits! This chip is not compatible with the old kits! 

Version history: please see http://www.qrp-labs.com/ultimate3/u3firmware.html

NOTE: 18-Dec-2021: The ATmega328 chip is now unobtainable at any distributors, due to the global semiconductor shortage. We have managed to obtain stock to be able to continue offering this item, however, the price was very high and this has necessitated a temporary price increase of $2.79 which is currently included in the price of this item.