4/3A 3800mAh Ni-MH Rechargeable 1.2v Batteries with Flat Top Pack of 4pc(they are not 1865mm size batteries) https://www.amazon.com/dp/B06XD45RZ9/ref=cm_sw_r_apan_glt_i_XN2MDTGZBCX490827W0J

I've used these for vapes, my head lamp has like 3 in it and it lasted as long as I needed it to. They are simple, cheap, and get the job done ✔️