If you have a PC, you can crack open the case and steal the jumper from the CMOS pin on the Motherboard, that works perfectly, just dont put it on the wrong pin (CLR) when you are done updating the B8.  Otherwise I would just search amazon for motherboard jumper and it should pop up with something pretty cheap like this:

https://www.amazon.com/Uxcell-a13112100ux0081-2-54mm-Standard-Circuit/dp/B00HR8DGZO/

or a penny and some electrical tape

#protip.... Tie a piece of string to it, it makes removal much easier