Racer X nailed it. Those are widely used and get decent reviews. Really no need to be experimenting with budget optics.

I know nothing of Dagger Defense but went to their website. This pic must be their flagship posted on the front page. Mount looks like is was put together from leftover parts.

I went to Amazon. 5th review down on one of their products... lens falls out, replacement not centered properly...

The quality of this item is very lacking from my experience, even for the price. My first one, the plastic "lense" in front (the bluish piece in the picture) completely rattle out just by driving in my vehicle on a dirt road to the range, making it worthless. The customer service was great and they sent me a new one free of charge. However, the next one also looks kinda shady and isn't centered properly in the frame. It aligns fine, but the quality just looks poor and I'm afraid to use it for fear of the problem happening again. I'd definitely buy a different brand.