I'm stunned at the ergonomics - Stark SE-5 Express Forward Grip

When I bought this, I imagined a "thumb-behind" hold like a tommy gun because the forward grip angle is identical to that model (and that is the second-most comfortable grip), but I have been inexplicably impressed by the ergonomics of the "thumb-up" hold of this particular AFG. First, it is a verified angled fore grip (AFG) according to the ATF and can be used with any pistol. Second, the questions I wanted answered before I bought it were more varied and intricate than I could explain. I will attempt to answer those questions here:

Complete grip weight: 3.21oz (91g)
Weight without plug: 2.82oz (80g)
Length of rail required: 3.875in (9.8425cm)(10 picatinny slots and gaps)
Height to bottom tip: 3.4375in (8.73125cm)
Grip width: 1.75in (4.445cm)
Depth of internal chamber (plug seated): 2.5625in (6.50875cm)
Grip back-sway past rail mount: 0.5in (1.27cm)

It weighs just a fraction of an ounce more than the Magpul AFG and contains a roomy compartment (I can easily fit a bore snake and 2x CR123 batteries). Grasping the grip on a whim offers a comfortable grip with 4 fingers on and thumb up, 3 fingers on/one in front and thumb up, or 4 fingers on with thumb behind. I prefer 4 fingers on with thumb up because I can easily reach my flashlight controls as well as absorb muzzle rise with my thumb. I never thought an AFG could impress me like this, but I am ordering another for my 10.5" AR pistol. This one was for the Extar EP9.