I'll be truthful I bought the $40 red dot sight and $15 riser years ago for my CZ .22LR dedicated upper. Horribly unreliable. Sight and riser ended in my parts box.

I've used a riser so rarely I don't know how the "height" is measured. The riser lifts the sight 3/4" above the standard rail. Top of the standard rail to the top of the riser rail when mounted.

The red dot is nicely co-witnessed with this 30mm tube. Red dot is split on the tip of the front sight post when looking thru the irons and both zeroed at 50 yards.

-- Chuck