You get what you pay for, it has no windage adj. but for loosening the eyepiece and sliding a tad L or R, guestimate at best. The fit and finish is average Italian repro. The elev 'vernier' is indistinct and the hardness of the screw is questionable, so keep it well lubed. I've seen them in the past in two heights.
That said, it is functionally probably as good, maybe better than most, of the 19th century.
If you are not shooting more seriously than casual competition it can be OK. All the guys I know who started with one have happily upgraded, but for funnin' around it may be good for you.
See Track of the Wolf and Buffalo Arms.
BTW, what the ad copy says is windage adj. (wrong) in the base are two opposing screws intended to get you a true verticle of the staff and locked down (get that version or be prepared to do some careful mounting to get the thing on straight & square