Duracell 700 Flashlight 18650 Mod

I got sick of buying batteries so I designed this. I printed it standing up with a 6 mm brim to keep it stable, it is 145 mm tall. I used a 4x1/4 inch flat head stove bolt with the slot ground down and cut to an overall length of 82mm. There is a countersink on the inside to accept the head of the bolt. This works with both flat top and button top 18650's.