TLR-6 Rail Mount - what secures it in place?

[socalbeachbum]

I'm interested in the Streamlight TLR-6 rail mount light for my Glock 19 but I am not seeing what hold it in place, is there a hidden set screw? Online photos do not seem to show anything.

 

[Arizona_Mike]

It clamps only the underside or frot it of the trigger guide depending on gun. It appears to have 3 hex screws holding the two sides of the clamshell together.

Mike