Battery should be change from tail end
Programming Tip: Twist the head so that the light is almost on but not quite. At this point squishing the head and the body together will make the light turn on like a momentary switch. Squish the light quickly 8 times to engage programming mode. Once in programming mode the groups selection doesn't need to be as quickly.
Note* WormVN has similar beam & output to ToolVN
Spec 3 Cu - 219C, Higher CRI with pleasant ~5000K neutral tint $150
Spec 4 Cu - XPL V6 Dome On 6000K , Brightest Floody Cool White $150