One of the greatest things about this guide scope is being able to lock it in place with the tiny screw on it. Finally I don’t ever have to worry about it being out of focus when taking my dew heater strap off it. I could tell a big difference in my subs after one night. I mostly take 180s subs and out of 100 I take each night I usually keep 80 to 90 of them because of the guiding accuracy. Hands down the best guide scope anyone could ask for.