Re: vortex viper ?
They are target turrets under the cap. I have the 4-16 HS and it's great. Marked in MOA and has rotation reference marks. It's a very good scope for long range. They're great and easy to use. and very easy to see.
"If God didn't want you to shoot a deer, he wouldn't have put a white target under their chins..." -Dad to a non-hunting preacher.