This is a 1/8 inch drill bit. We use this for drilling a hole that will take a #4 machine screw. The majority of our kits and circuit boards use a #4 machine screw so this drill bit size is a must for putting together a robot kit.
The B3 Compact charger is a very simple to use charger for 2S and 3S battery packs. No need for additional power supplies or 12v batteries as this little unit has its own built in power supply that can be powered with 100-240v.